Since I upgraded my MacBook Pro(mid-2012) to macOS Sierra the voice which is being used by Siri is unnatural.It sounds like the old iOS 6 Siri.I downloaded all the dictation voices but the problem persists.Somwhere on the internet I found a solution saying that enabling checkboxes under App Store auto-update fixes the issue but Siri still sounds the same.Does anyone have a concrete solution?

One thing I've noticed while using Siri on macOS Sierra is that Siri's voice is not natural (not even close to natural, it sounds like the default system voice of my Mac). How can I get Siri on macOS to sound as high-quality and natural as Siri on iOS?  I have downloaded Samantha voice for Mac before. I even tried deleting Samantha's voice and redownloading it, but Siri's voice is still like a robot!  When I change Siri's voice to Male (or any other accent or language) and then revert it back to Female, the voice gets better (still not the Siri I have on my iPhone), but then again after a few moments, it's back to default system voice.  What is going wrong here?


Several months ago I was looking at one of my posts, and I noticed an up vote started to toggle. The vote count incremented by one, then decremented again, cyclicly. At my end the rate seemed faster than 2 Hz, and the toggling continued for several seconds. Say 10 full up-down cycles in all, as a short burst.  It felt a bit spooky, as if someone was trying to "send me a message" and that's weird because there's never been a case of non-verbal communication in SE ;-)  I'm wondering if there is an upper limit to the rate at which someone can indecisively toggle an up vote, or on the total number of toggles, before SE bots say "that's enough", or a limit on what people on the other end see?   Because of the way packets route, I assume this can't be easily used to send secret messages without sever corruption because the timing information is lost, at least as far as the viewer sees on the screen.  Is this a "known thing" and I'm just the last person to find out?

I noticed that I can only perform certain actions such as commenting a finite number of times in a given period of time. Obviously, rate limiting is in place to prevent accidental misuse or intentional abuse of certain features.  Where else is rate limiting applied on Stack Exchange sites, and what are the limits?


How the equals function knows s1 having the null reference to the String.

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


A capacitor has insulating material between plates and this insulting material does not provide any electrical or conducting path between capacitor plates. But still, capacitor allows DC or/and AC current to flow through it, How?

Sorry, i am novice in electronics, trying to understand basic fundamental of electronics.  1. How does capacitor conduct current when two plates aren't physically connected.


I have started to learn how to write statements in Java. I have seen on Stack Overflow prepared statements that have values, but I was wondering how I could write something like my statement to become a prepared statement.  This is my code:  public void put(MySQLDatabase mysqlDB) {     if (mysqlDB != null) {       boolean bool = mysqlDB.setMySqLData("UPDATE Person SET personName = '" +         personName +         "', personDescr = '" + personDescr + "', personAge = " + personAge + "         WHERE personId = " + personId);     } }  public void post(MySQLDatabase mysqlDB) {   if (mysqlDB != null) {     boolean bool = mysqlDB.setMySqLData("INSERT INTO person VALUES(" + personId +       ", '" +       personName + "', '" + personDescr + "', " + personAge +       ")");   } }  public void delete(MySQLDatabase mysqlDB) {   if (mysqlDB != null) {     boolean bool = mysqlDB.setMySqLData("DELETE FROM person WHERE personId=" +       personId);   } }   I don't know if it is possible to do it like this and I would like to know if I would have any benefits doing a prepared statement for these queries.

I am planning to replace repeatedly executed Statement objects with PreparedStatement objects to improve performance. I am using arguments like the MySQL function now(), and string variables.   Most of the PreparedStatement queries I have seen contained constant values (like 10, and strings like "New York") as arguments used for the ? in the queries. How would I go about using functions like now(), and variables as arguments? Is it necessary to use the ?s in the queries instead of actual values? I am quite confounded.


I have received downvotes on my Stack Overflow Qt questions. As those downvotes are all within 1 minute, I doubt they are justified. Strange, they only cover my Qt questions, not the latest.  How could that happen?

I just noticed that I lost a bunch of points from my reputation score, and I used the "reputation" tab on my user profile page to try and track down the cause.  During my investigation, I noticed there was an unusual event of type "reversal". In the normal place of a question title, it says "voting corrected".     What does this mean, and what caused it?  Did I do something wrong? Why did I lose all of that reputation? Is the system punishing me for leaving too many good answers?  Is there any way to earn it back?


I want to find the cost of all my tolls and estimate on total gas for my trip from Mexico, ME to Chittenango, NY which is 385 miles shortest distance driving a 17 foot U-Haul truck, averaging roughly 10 miles to the gallon.

Is there a convenient way to calculate the cost of tolls between two arbitrary points within the United States? I'm planning to take a trip along the Eastern seaboard and will be passing through multiple states with different toll-collecting authorities. The mapping and trip planning resources I've found so far will only indicate whether a particular section of road has tolls, not the price of those tolls. I'm aware that the various toll-collecting authorities post their rates online, but these charts are often difficult to use if you're not already familiar with the area. Isn't there an easier way?


Problem: The product of two quotient maps need not be a quotient map  I started proof by followings  Let $X=\mathbb{R}$ and let $X^*$ (obtained from $X$) be the set identifying the subset $\mathbb{Z}^+$ to $a$ point $b$ And let $\mathbb{Q}$ be rational numbers  Claim : 1)  $p$: $X\to X^*$ be the quotient map.  2)  $q$: $\mathbb{Q}\to\mathbb{Q}$ be identity map then $q$ is quotient map 3)  $p\times q$: $X\times \mathbb{Q}\to X^*\times\mathbb{Q}$ is not quotient map  I want to know how to prove $1$, $2$, and $3$ In particular, why $p$ is surjective

I am looking for easy(!) counterexamples that the product of two quotient maps is not necessarily a quotient map and that the quotient space of a Hausdorff space is not necessarily Hausdorff.


So I recently tried to install playonlinux on Ubuntu 16.04 and it was installing but stopped halfway through the installation, so I closed it and that was where I messed up. Now every time I enter  sudo apt-get update   in the terminal the error is:  E: Type '--2017-01-12' is not known on line 1 in source list /etc/apt/sources.list.d/playonlinux.list   E: The list of sources could not be read.

Every once in a while I see users having issues to update due to errors like this:  E:Type 'ain' is not known on line 1 in source list /etc/apt/sources.list.d/some-ppa.list'   with varying types/line numbers/source list files (often after removing a PPA).  How can such an error be fixed?


Suppose that M,N, and P are the midpoints of sides AB, AC, and BC of triangle ABC. Show that the centroid of triangle MNP is the same point as the centroid of triangle ABC.

The question is as follows:      Let $A'$, $B'$ and $C'$ be the midpoint triangle of triangle $ABC$. In other words, $A'$, $B'$ and $C'$ are the midpoints of segments $BC$, $CA$ and $AB$, respectively. Show that triangles $A'B'C'$ and $ABC$ have the same centroid.    My reasoning was through the means of the Midline Theorem. After drawing the diagram, we can see, for example, $C'A'$ is a midline of $\triangle ABC$, which means that $C'A'$ is parallel to the base $AC$ and half the length of it as well. Therefore, the median $B'B$ would pass through the midpoint of $C'A'$, including the midpoint of $AC$.   Is my reasoning valid or, at least, is it on the right track? Any advice on solving this problem will be greatly appreciated.


i tried it like this:  we need 6 places to put the $ 1,2,3,4,5,6 $ numbers on top face and in rest of the places we don't care.  So number of favorable cases is   $$ ^nC_6*6!*6^{n-6}$$  My total number of cases are $6^n $  So my probability is $$ ^nC_6*6!*6^{n-6}/6^n$$  but it's wrong. where am i wrong?

Sample $k$ times with order from $n$ distinct numbers with replacement where $k\ge n$. Here "with order" means the sample is treated like a sequence rather than a set, so results like "1,3,3" and "3,1,3" are different.  The question is what is the probability that every number is sampled at least once? My answer is $1-\frac{{\sum\limits_{i = 1}^n {C_n^i\times i! \times {{(n - i)}^k}} }}{{{n^k}}}$ where $C_n^i$ denotes $n$ chooses $i$.  ${C_n^i\times i! \times {{(n - i)}^k}}$ means first choose $i$ ($i=1,2,...,n-1$) of numbers not to appear in the sample, and then we sample from the remaining $n-i$ numbers for $k$ times.   My question is, is there more elegant solution where the numerator can be directly computed? i.e. can we directly calculate the number of possible sample sequences in which every number has at least one occurrence? Thank you!    PS: my attempt was $C_k^n\times n!\times n^{n-k}$, meaning that we first choose $n$ positions in the sequence of length $k$ to place $n$ numbers, and then permute the $n$ numbers. This is to ensure every number to appear once. The remaining $n-k$ are sampled from the $n$ numbers without restriction.   However, I later found this seems not correct, and it counts the same sequence multiple times.  PS2: as pointed out in the comments, my first answer "1- ..." is not correct either.


I was searching for a solution to a very practical problem asked by a friend of mine. The problem was that he had to lay a dropped kerb to allow vehicular access to customer's property... except the kerb was on a road bend. Since I am the closest person that he knows to qualify as a civil engineer, so he asked me to find a formula that could be used for this purpose. In the image is a diagram with workings to create the final formula for the unknown radius. My question is this: Is the formula and derivation universally correct?   My result was $$r=\dfrac{4B^2+A^2}{8B}$$ Where B is the perpendicular height from midpoint of arc to midpoint of chord and A is the length of the chord itself.  I am concerned that I introduced an error in part 2 of the 3 steps of evaluation. Can anyone refute this?

I have a (circular) segment of known height and known chord length. Is is possible to determine the radius of the circle?  Any help much appreciated.


it seems bad luck also likes me.! i'm trying to install mongo DB but facing issue while updating apt-get repository as below  Reading package lists... Done    E: The repository 'http://repo.mongodb.org/apt/ubuntu bionic/mongodb-org/3.0 Release' does not have a Release file. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details. W: GPG error: http://repo.mongodb.org/apt/ubuntu xenial/mongodb-org/3.4 Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY BC711F9BA15703C6 E: The repository 'http://repo.mongodb.org/apt/ubuntu xenial/mongodb-org/3.4 Release' is not signed. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details. W: GPG error: http://cz.archive.ubuntu.com/ubuntu precise Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 40976EAF437D05B5   i suspect that something messed up with /etc/apt/sources.list.d  Can anyone help me how could i resolve this and install mongo DB.  Many Thanks, Surya Kiran.

I added some extra repositories with the Software Sources program. But when I reload the package database, I get an error like the following:     W: GPG error:  trusty InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 8BAF9A6F   I know I can fix it using apt-key in a terminal, according to the official Ubuntu documentation. But I would have liked to do it graphically. Is there a way to do this without using a terminal?


I have successfully installed full Ubuntu on a USB 3 stick drive. I mainly use Win 10 but my aim is to be able to boot into the Ubuntu stick drive by simply plugging the stick in before booting. I have set the boot priority order in BIOS to Ubuntu stick > Windows boot Controller > etc etc However, when I boot to Ubuntu and wish to return to a Win 10 by removing the USB stick and rebooting the system requests a Grub response. Then I have to reboot change the boot order in BIOS to Windows > Ubuntu. Is there a way to occasionally boot to the Ubuntu stick without having to continually reset boot order in BIOS ?

what I want to do is this. I have an external hard disk drive, a SEAGATE expansion 1TB, you can take it a look here:  As you can see this is not a flash usb hard drive, it is a USB hard disk drive. What I want to do is installing Ubuntu in this external hard disk drive... BUT NOT PLACING THE GRUB ON MY C: DRIVE. In other words, I don't want to see the GRUB splash Window asking me every single time if I want to load Windows or Linux. I want my PC turn on or restart and go directly to Windows... BUT... I want to have Linux in my external USB hard disk drive How do I want to load Ubuntu then? Easy, when I restart my computer or just start it... in ASUS mother boards I have the possibility to select the boot device by pressing F8, and I get the boot menu. I want to turn on my computer, press F8, my mother board ask me what drive I want to use to load the Operating Sytem, I select the USB external hard disk drive where do I have Ubuntu, and bingo, I run Ubuntu. When I finish to use Ubuntu, I close it and turn off my computer. Later, I turn on my computer, and if I don't press F8, automatically load the hard disk drive C: and load Windows. My question about this, is what are the necessary steps to install the latest version from Ubuntu, doing exactly this. Not placing the GRUB in my C: hard disk drive, and installing it entirely in the external USB hard disk drive (normal one, not flash one).


I tried to download it on  but the only version are 64 bits. My question is the title, is it possible to download Chrome 32bits?  English isnt my first language sorry for mistakes, Thanks you!

Where can you download 32 bit edition of Google Chrome for Ubuntu OS?


On Windows (MiKTeX), lualatex has a --aux-directory switch. On Linux (TeXLive) it does not. Why is that? If it is a downstream patch only present in MiKTeX, why is it not in upstream lualatex?  It seems like the same issue affects pdflatex and other engines

I want to make one global folder for all auxiliary files which are produced while compiling .tex file (i.e. .aux, .log, .out, .toc, synctex.gz). I use TeXstudio and I found that I have to change compiling options in Configure TeXstudio > Commands. Now I have   pdflatex.exe -synctex=1 -interaction=nonstopmode -aux-directory="C:\Latex_Aux_Global" %.tex    for PdfLaTeX, which moves all files except .synctex.gz file. It is possible to move this file to the same directory as all auxiliary files?  My second problem is that I need to use also BibTex and MakeIndex connected with this global folder Latex_Aux_Global. For BibTex I have following command  bibtex.exe "C:\Latex_Aux_Global"/% -include-directory="C:\Latex_Aux_Global".   I don't know in what way I can make such command for MakeIndex. When I use   makeindex.exe "C:\LaTeX_Aux_Global"/%.idx    to MakeIndex, while compiling I get error Can't create output index file C:\LaTeX_Aux_Global/document.ind. I will be gratefull for any suggestions.


narayan@josh:~$ sudo apt-get install root-system-bin  E: Could not get lock /var/lib/dpkg/lock - open (11: Resource temporarily unavailable) E: Unable to lock the administration directory (/var/lib/dpkg/), is another process using it?

I get this error when trying to use apt-get:  E: Could not get lock /var/lib/dpkg/lock - open (11 Resource temporarily unavailable) E: Unable to lock the administration directory (/var/lib/dpkg/) is another process using it?     How can I fix this?


I will start by saying that after reading  about a declined feature request to allow moderators to grant commenting privileges, I am skeptical that my suggestions/thoughts will get positive feedback, but I will try anyways since I think there are real and unsolved problems regarding this topic.  In the question asked  regarding the necessity of 50 reputation as a bar for allowing comments, the most highly voted answer specified that the main reason is spam protection. This makes sense to me, and I completely understand that giving new users the ability to comment right away (or almost right away) will create a flood of comments with no actual value.  From my very limited stackexchange experience, it seems that in some communities, getting 50+ reputation can actually be very challenging. For example, in math.stackexchange, since mathematics is such a huge area, finding new and trending questions one can answer is actually a difficult task, unless one is truly a math expert (at the very least a graduate mathematics student). In addition, it also seems that contributing to older posts (even ones without an accepted or a complete answer) will usually not earn the user new thumbs: there are many posts that are a couple of years old, and these mostly stay inactive even if new and valuable information is added. This is also true for suggesting edits to older posts. I am sure there are other communities that pose similar challenges for responsible beginners who aren't already experts in the field. I want to emphasize that when I say beginners I don't mean high school students: even excelling undergraduate math students will have no chance to answer the vast majority of new questions.  Therefore, I think that considering new ways to earn the basic privileges of the site (mainly commenting), such as time since registration, number of days performing an activity etc' can be beneficial. This will still prevent new users from creating an account immediately after they found a single relevant question and automatically starting to comment on it and related posts. However, users who are responsible, are truly interested in being long-time stack exchange members and didn't join just to ask a question and disappear, will always eventually be able to be more fully participating members.   I am sure such a feature will also lower the amount of content posted as answers posted simply because the user doesn't have commenting privileges, which to my understanding is a relatively common and unwanted phenomenon, which shouldn't be suggested as a workaround. Commenting can also be more likely to properly revive an old inactive post, since it directly notifies the relevant answerer rather than the asker.  Edit: explaining the difference between my question and : In my opinion, the association bonus provides a full solution to the problem described in the other question, which was sharing reputation across different stackexchange forums. My problem is not concerned with sharing reputation per se, but with the initial problem of obtaining reputation in a single forum to begin with. For example, many undergraduate students use a single stack exchange forum to help with their studies, and might not have other interests or knowledge relevant to other forums, in which case the association bonus will be of no use. As I stated in the comments, I think the association bonus is still a good partial solution, but it is not a full one. I might accept one of the answers mentioning it since it is significantly better than nothing.

I was just awarded +100 reputation on all of my Stack Exchange accounts.  What is this bonus for? It simply says "Association Bonus" on my reputation overview.  Also:   What privileges does the association bonus grant users? Can I lose the association bonus? Does it make my reputation 101 everywhere? Can I earn the association bonus on sites I haven't joined yet? Does it matter which site I earn the 200 reputation on? Will I get an association bonus every time my reputation on a site crosses 200 points? Does the association bonus allow me to answer protected questions? Does the association bonus count towards the reputation cap? Can I get the association bonus if I only have a profile on one site? What else is there to know about the association bonus?


Let $F$ be a field containing a primitive $n$-th root of unity (for $n \geq 2$) and let $E = F(\alpha)$ where $\alpha \in E$ is an element whose $n$-th power (but no smaller power) is in $F$. Let $\alpha^n := a$.  Question: Assuming $p$ is an arbitrary prime dividing $n$ and $a$ is not a $p$-th power, why is the polynomial $X^n - a$ irreducible in $F[X]$?  What I did by myself?  I know that the roots of $X^n - a$ must be $\zeta^i \alpha$ for $i=0,\dots,n-1$ and $\zeta \in F$ being the primitive $n$-th root of unity from the assumption.  I also know that $E/F$ is a cyclic Galois of order $n$. A generator is $\sigma: \alpha \mapsto \zeta \alpha$.   Is there a way to use one of these facts to prove the statement? If not, what can I do differently? Thanks in advance!

Let $F$ be a field, let $\omega$ be a primitive $n$th root of unity in an algebraic closure of $F$. If $a$ in $F$ is not an $m$th power in $F(\omega)$ for any $m\gt 1$ that divides $n$, how to show that $x^n -a$ is irreducible over $F$?


I have iMac, late 2011, Intel CPU.  Original OS X was Leopard updated to High Sierra.  Hardware cannot update to any later version.  Installed Windows 7 using Bootcamp in High Sierra.  Updated Windows 7 to Windows 10. Windows 10 had problems, i.e. System Restore did not work, a driver for Bluetooth not installed.  I decided to try a clean install of Windows 10. But Bootcamp setup file prepared under High Sierra says it requires Windows 7. Because of problems when update Windows 7 to 10, is it possible to install Windows 10 without starting with Mac OS X / Windows 7?  Note: Windows 10 will do a clean install (everything on drive deleted, reformat as 1 NTSF partition during Windows install). Bootcamp setup will open in Windows 10 but stops and states it requires Windows 7. Is there another version of Bootcamp available?  Note: Without Bootcamp, after installation, Windows 10 gets stuck when restarted. I get Mac white screen, then Windows blue flag with spinning dots. Screen blacks out, then starts over with Mac white screen. Repeats indefinitely. (However, no problem restarting during install process.) Thanks for any information.  Bad news accepted, just want to know if this is possible and how to do it. If not; I'll deal with it.  Many thanks in advance.

Apple does not support Boot Camp Assistant installations of Windows 10 on 2011 and earlier iMac models. The exact list of supported Mac models is given below.  The following Mac models support 64-bit versions of Windows 10 when installed using Boot Camp.      If you have one of the models listed below, then you should not use the accepted answer to install Widows 10.    MacBook Pro (2012 and later) MacBook Air (2012 and later) MacBook (2015 and later) iMac (2012 and later) Mac mini (2012 and later) Mac mini Server (Late 2012) Mac Pro (Late 2013)   I have read where others have successfully used the Boot Camp Assistant to create a Windows flash drive installer. This was accomplished by first editing a .plist file contained within the Boot Camp Assistant software. I have the following problems with doing this.   The Boot Camp Assistant software has to be hacked in order to create the Windows installer. The resulting flash drive installer defaults to a Windows installation that uses the EFI boot method. Apple did not officially start supporting this method of booting Windows until the 2012 model year. I have always assumed the Windows Support Software, supplied by Apple for my Mac, was designed only for the legacy BIOS boot method of installation.       I have no problems EFI booting the USB Windows installer, but I still want to install Windows to use the BIOS boot method.    Here is what I wish to accomplish.   Install Windows 10 Pro 64 bit. I have downloaded the latest Windows 10 (Version 1709, OS Build 16299.15) iso file. Install Windows 10 into a newly formatted volume. I do not want to first install an earlier version of Windows and then upgrade to Window 10. Boot Windows using the legacy BIOS boot method. Use only one partition on the first internal drive (disk0) for the Windows files.  The single internal disk in my Mac uses a 512 byte sector size. Install Windows using the latest version of macOS. Currently, this would be High Sierra (macOS 10.13.2).   I would desire to preform the installation without any of the following.   No third party software No optical (DVD) drive  No Boot Camp Assistant Without disabling System Integrity Protection (SIP).   I would prefer not having to boot to  via the internet, built-in recovery or an . But, since  is not a third party tool, I am not opposed to its use.


I'm somewhat new to Blender. I have a simple mesh that I used proportional editing on. Now I want to straighten out the outer four corner edges. (ie the selected vertices when the .blend file opens) I've seen some answers but can't get them to work. Thanks for any ideas to try.  Here's the copied link to the .blend file:    Thanks for any ideas.  edit: okay, thanks, here's a picture...wondering how to straighten out that line of vertices, thanks again for any ideas  edit: @Brian, Okay, so now my question is how to make it so, in this second image, these two selected vertices are on an axis? Then I can then select and scale the rest of the line of vertices and scale them to that axis. I don't know how to align these two vertices to any axis. Thanks.  (Well, forget that second image, not enough reputation to post two links, so the vertices I'm talking about are on the left side of the first image, the topmost vertice, and the fourth up from the bottom.)  @Jesse Can you get the line of vertices I refer to to line up in a straight line between the two vertices I'm referring to with this technique? I couldn't do it.

I have some edges that are not on the x, y or z axis. What is a simple way to straighten them? For example, I can scale and then use Shift+Z to straighten on the x and y axis.  Any shortcuts other than temporarily rotating the entire object to put the edges on an axis?


Is this sentence structure correct ?      A society so vibrant and diverse as America’s is bound to dominate.   My basic confusion is that whether to put ’s at the end of the subject or not.   Another example:     A personality so mannered and educated as John’s always has a bright future.

When learning how to make comparisons, students of English as a foreign language are first told to use the structure "as [adjective/adverb] as". However, at higher levels, they are told that both options ("as/so [adjective/adverb] as") are correct.   I've been wondering if there are any differences between them, but I can't find an answer in my grammar (Cambridge Grammar of English). In a school book, I saw two examples that led me to think that:   "as [adverb] as" is possible with both positive and negative sentences "so [adverb] as" is only possible in negative sentences   Is this correct? If so, does it also apply to adjectives?  Examples for adjectives:   This is as good as that.  This is so good as that. This isn't as good as that.  This isn't so good as that.   Examples for adverbs:   Anne plays as well as John.  Anne plays so well as John. (not correct?) Anne doesn't play as well as John. Anne doesn't play so well as John.


Is buying smart electronics worth the price?  This is the title of an article I am trying to write. Buying is one action,  but electronics is plural. What if I said, "Is it worth the price to buy smart electronics?"  Are buying smart electronics worth the price? sounds better I think

Making adult decisions are/is really not fun.     What is the proper answer and why? My gut says "is" but I can't explain why.


I am trying to create a nav bar and i don't know why i am facing this problem : Trying to set the li within the ul as inline-block works, but it is moving the whole list below the image i am using as a logo. Can someone explain why is this happening and how to fix it?    * {   margin: 0;   padding: 0;   box-sizing: border-box; }  body {   background-color: black; }  img {   display: inline-block;   width: 100%;   height: auto;   background-position: center;   background-size: cover;   background-repeat: no-repeat; }  .logo {   width: 150px;   position: center;   display: inline-block; }  #nav-bar {   background-color: yellow; }  ul {   list-style-type: none;   margin: 0;   padding: 0;   display: inline-block; }  #nav-bar li {   display: inline-block; } <!DOCTYPE html>         <meta charset="UTF-8" />     <meta name="viewport" content="width=device-width, initial-scale=1.0" />     <title>Document</title>     <link rel="stylesheet" href="style.css" />

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I have a div with two images and an h1. All of them need to be vertically aligned within the div, next to each other. One of the images needs to be absolute positioned within the div. What is the CSS needed for this to work on all common browsers?

testing...


We are standing on the Earth and we see Sun on the sky. We see it walking in a certain direction, with predictable moving. Earth is a spheroid, as we all know. It is circling around the Sun, and also it is circling around its own axis which is in the certain plane.  Why Earth is orbiting in the plane, and not in randomly like a ball? So, if it orbits randomly, then a Sun path on the sky would be a continuous random path and we could have days and nights in the same day a lot of times. Why is that not happening? Which force is acting on the Earth so that Earth is rotating around its own axis in that certain plane, and not randomly?  Also, Earth is moving with a certain speed and never has earthquake of higher degree so that we could see Sun on the sky as making Electrogardiographic curve. Why is that not happening and the speed of our Galaxy is so huge?

Most images you see of the solar system are 2D and all planets orbit in the same plane. In a 3D view, are really all planets orbiting in similar planes? Is there a reason for this? I'd expect that the orbits distributed all around the sun, in 3D. Has an object made by man (a probe) ever left the Solar System?


When I do  >>> a = [1]*3 >>> a  [1,1,1] >>> a[0] = a[0]+1 >>> a  [2,1,1]   which is perfectly fine, but when I do the same with sets iget the following  >>> a = [set()]*3 >>> a [set([]), set([]), set([])] >>> a[0].add(1) >>> a  [set([1]), set([1]), set([1])]   Which is a very strange behaviour, any explanation for this?

I needed to create a list of lists in Python, so I typed the following: my_list = [[1] * 4] * 3  The list looked like this: [[1, 1, 1, 1], [1, 1, 1, 1], [1, 1, 1, 1]]    Then I changed one of the innermost values: my_list[0][0] = 5  Now my list looks like this: [[5, 1, 1, 1], [5, 1, 1, 1], [5, 1, 1, 1]]    which is not what I wanted or expected. Can someone please explain what's going on, and how to get around it?


I hear many native speakers say, for example, "glad to connect" or "Not sure about that". Where they delete "I am" at the beginning of the sentence, Is that kind of "short the talk", I mean to speak a fewer words, or it has a conditions/rules to delete those words?

At the end of a letter, is it correct to omit "I am" in this sentence?     I am looking forward to hearing from you   Then it will become:     Looking forward to hearing from you


I'm trying to retrieve data from mysql database using php and mysqli  but when the result show up there is some fields that are not complete for example: the field in the database is: domaine de l'agricultule but when it show up is like: domaine de l      echo "<input type='text' name='domaine' size='80' dir='ltr'    value='{$row['domaine']}'/>";   help please where i the problem!

If user input is inserted without modification into an SQL query, then the application becomes vulnerable to , like in the following example:  $unsafe_variable = $_POST['user_input'];   mysql_query("INSERT INTO `table` (`column`) VALUES ('$unsafe_variable')");   That's because the user can input something like value'); DROP TABLE table;--, and the query becomes:  INSERT INTO `table` (`column`) VALUES('value'); DROP TABLE table;--')   What can be done to prevent this from happening?


I have a folder in ~ called work that contains all my work. Usually when I start an instance of Terminal I type cd work. I would like to avoid this because it's very repetitive. I tried putting cd work in my .bashrc but I realized that I don't always want to cd work - for instance, when I Open Terminal here or when I open a Terminal in VSCode (which should open my Terminal in the current project directory, not work). My idea is having the Terminal type out cd work whenever I open it, but not actually execute the command. If I really need to cd work, all I have to do is hit Return. However, if I don't want to do that, I can just Ctrl+C. Is doing this possible?

Rather than rephrasing my question, let me describe to you the desired user-case:  I create a short shell-script to run command "gnome-terminal --someoptionflagname 'my text to be posted'", and execute this script.  Gnome-terminal pops up, with command-line prompt followed by my text.   ie: fields@mycomputer:/$ my text to be posted  Can this be done?


What's the rule for using a/an before an adjective?  I am asking this question because my high school professor is teaching us that  we shouldn't use a/an before an adjective. With some 'exceptions' like "Picasso was a famous painter."   Now that sounds very strange to me because I am used to saying "It's a beautiful day.", not "It's beautiful day.", or "It's a small dog.", not "It's small dog". My professor also pointed out that "Picasso was a famous painter." was some kind of exception because "a" is used before an adjective. My professor also told me that this sentence is correct : "A mouse is an animal. It's small animal."  Like I said, for me, It's a very strange claim that we shouldn't use "a" or "an" before an adjective. What should I say to my professor? I would like your professional opinion about this.  Thanks.  Notice: This question isn't about 'a' vs 'an'. Read the question before marking it as a duplicate.

I can’t for the life of me figure out where to use a and where to use the — and where there is no article at all. Is there a simple rule of thumb to memorize?   The standard rule you always hear:     “If a person knows which item you are talking about then use "the"   . . . doesn’t clear things up for me, as I have no idea whether or not they know.


So in my QFT course, my professor said that you can set $c$ and $\hbar$ to 1. And he gave us an example: $$E = mc^{2}$$ And then set $c = 1$: $$E = m$$ This seems completely ludicrous to me to do. Doesn't it change the result? Why can this be done and why isn't it wrong? I mean, $E = mc^{2}$ gives you one answer and $E = m$ gives you another, completely different answer!

I understand the idea of swapping from unit systems, say from $\mathrm{m\ s^{-1}}$ to $\mathrm{km\ s^{-1}}$, but why can we just delete the units altogether?  My question is: what exactly are we doing when we say that $c=1$?


I am running a LASSO regression, but am put off by the different values of lambda each time I run the cross-validation. Does it make sense to run a cross validation multiple times, take the mean error associated with each lambda value, and then choose lambda.1se (i.e., the largest lambda resulting in error within 1 se of the minimum) from the distribution of lambdas and mean errors?  library(glmnet) set.seed(3)  IV1 <- data.frame(IV1 = rnorm(100)) IV2 <- data.frame(IV2 = rnorm(100)) IV3 <- data.frame(IV3 = rnorm(100)) IV4 <- data.frame(IV4 = rnorm(100)) IV5 <- data.frame(IV5 = rnorm(100)) DV <- data.frame(DV = rnorm(100))  data <- data.frame(IV1,IV2,IV3,IV4,IV5,DV) x <- model.matrix(DV~.-IV5 , data)[ , -1] y <- data$DV   lambdas <- NULL n.fits <- 100 for (i in 1:n.fits) {     {   fit <- cv.glmnet(x,y)   errors = data.frame(fit$lambda,fit$cvm)   lambdas <- rbind(lambdas,errors)   r2[i]<-max(1-fit$cvm/var(y)) } # take mean cvm for each lambda lambdas <- aggregate(lambdas[, 2], list(lambdas$fit.lambda), mean) lambdas<-as.data.frame(lambdas)  # find subset with mse within 1 se of mean onese<-std.error(lambdas[2]) min<-min(lambdas[2]) low<-min-onese high<-min+onese  lambdas<-subset(lambdas, x>low) lambdas<-subset(lambdas, x<high)  #choose highest lambda among those  bestindex = which(lambdas[1]==max(lambdas[1])) bestlambda = lambdas[bestindex,1]   Edit: My question is unique because I am asking about how to implement the one standard error rule after iterating the cross validation.  Edit 2: It's possible my question isn't clear. I am being linked to a previous question which is different. That one talks about running cross validation once and choosing the best lambda from that process. I would like to run cross validation multiple times, averaging over the different results, and choosing the best lambda based off of that. I would like to know if my code is an acceptable way of doing that.

I'm studying LASSO regression, in particular the choice of the optimal tuning parameter.  The glmnet package and the book "Elements of Statistical Learning" offer two possible tuning Parameters: The $\lambda$, that minimizes the average error, and the $\lambda$, selected by the "one-standard-error" rule.  I couldn't find any research or evidence on    the "one-standard-error" rule, and which $\lambda$ I should use for my LASSO-regression.   EDIT: From the textbook elements of statistical learning   "Often a “one-standard error” rule is used with cross-validation, in which we choose the most par- simonious model whose error is no more than one standard error above the error of the best model."


I'm new with android development. I'm currently developing an Android Application on Face Recognition. I'm trying to run an existing source code that I obtain from github. The codes seems does not have any error(red line beneath the code). When I tried to run, the application has stopped working and gave me a java.lang.NullPointerException error.  Caused by: java.lang.NullPointerException            at java.util.Objects.requireNonNull(Objects.java:98)            at com.example.syafiq.testing.FdActivity.onCreate(FdActivity.java:179)   on the highlighted error (FdActivity.java:179)  (line 178) ActionBar actionBar = getActionBar(); (line 179) actionBar.setDisplayHomeAsUpEnabled(true);   I've tried solution that I've found on the Internet  First try:  ActionBar actionBar = getActionBar(); assert actionBar != null; actionBar.setDisplayHomeAsUpEnabled(true);   And yet still the same error, so i tried another one that I found on the Internet.  Second try:  ActionBar actionBar = getActionBar();     if (actionBar != null) {         actionBar.setDisplayHomeAsUpEnabled(true);     }   The result still the same I've tried the third one  Third try:  ActionBar actionBar = getActionBar(); Objects.requireNonNull(actionBar).setDisplayHomeAsUpEnabled(true);   All the three solution that I've tried still giving the same error, point to line 179   For android manifest.xml(obtain from source code on github):  android:theme="@android:style/Theme.Holo"   But the source code does not have style.xml file under the values folder. But my android studio include with style.xml file and the code is:  <style name="Theme.Holo" parent="Theme.AppCompat.Light.DarkActionBar">   I did not use the import tools instead I've created manually (.java, .xml and other libraries that included)

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


The k-means implemented in scikit-learn precomputes distances but I don't how these distances are used. In its standard version, k-means is known to compute only the distances between the points and the centers. I am wondering if a pariwise distance matrix is useful to k-means.  Thank you for your help.

Is there a specific purpose in terms of efficiency or functionality why the k-means algorithm does not use for example cosine (dis)similarity as a distance metric, but can only use the Euclidean norm? In general, will K-means method comply and be correct when other distances than Euclidean are considered or used?  [Addition by @ttnphns. The question is two-fold. "(Non)Euclidean distance" may concern distance between two data points or distance between a data point and a cluster centre. Both ways have been attempted to address in the answers so far.]


Is it possible to go from HDMI to active dual link DVI with a resolution of 2560 x 1600px ? I have a Lenovo E540 laptop, and it only got a HDMI and a VGA out, but I have a 30" Mac Cinema HD screen, which only has a DVI connector.  From several searches I can see that there are plenty of Displayport to active DVI converters, but none from HDMI to active DVI. Now is my question if it's possible to convert HDMI to displayport and go from there with a displayport to active DVI converter. Or is this not possible? If not, are there other possibilities?

My monitor supports full-resolution display (2560x1440) only when connected to through either the DVI-D dual link port, or the DisplayPort.  My laptop, though, has neither of these two kinds of output. Instead, all it's got is a HDMI port (which is version 1.3, and I also read that the laptop's graphics chipset supports 2560x1440 at 60Hz).  So I'm wondering whether anyone has ever seen an HDMI-to-DVI dual link adapter, which will carry my ultra-highres signal to the monitor I just bought. So far I haven't seen any, and don't even know whether such an adapter (which I understand would have to be active, USB-powered and expensive (but I don't care)) exists.


There is a univariate mean: sum the points and divide by the count.  There is a multivariate mean analog - the centroid, a point in a multidimensional space.  ().  For the median one sorts the list and picks the middle element.  If the middle element doesn't exist, the nearest values to it are averaged.  ()  It is an ordered statistic.  If I were to make a cloud of points in 2d space, then median might depend on what I defined as an axis.  If my cloud was more like a needle, then median might vary greatly with very slight changes in semi-minor axis, because it could flip from one tip to another of the cloud.  Is there a generalized geometric analog of the mean - something that uses an analog of an ordered statistic in a non-univariate space?  If I had well behaved cloud, even if it was more needle-like, I would expect such a median to have a reasonable correlation with and proximity to a centroid.  It was suggested that this () contains the answer.  When I try to find the point that gives the least typical distance, the results are consistent with a geometric mean.  #CODE n <- 1000 xmin <- 0 xmax <- 10 ymin <- 0 ymax <- 10  #make some points x <- runif(n,min=xmin,max=xmax) y <- runif(n,min=ymin,max=ymax)  #plot plot(x,y,type="p")  #find "geometric median" mu <- 0  for (i in 1:n){    xp <- x[i]   yp <- y[i]   d <- sqrt( (x-xp)^2 + (y-yp)^2 )   mu[i] <- mean(d)  }  idx <- which(mu==min(mu),arr.ind=true)  points(x[idx],y[idx],col="Red",pch=16) points(mean(x),mean(y),col="Blue",pch=17)   I get plots that look like the following.  The red point is the "idx" of the least typical distance to all other points.  The blue triangle is the centroid.  The red circle is the "geometric median".    To me the image seems to confirm that the approach to the median is consistent with the mean.  I have not accounted for an odd number of points, but I think that using uniform random and an $$ L_2 $$ norm is unlikely to give me two candidate medians with the same distance to all other points.  So I tried to determine the error in the estimate of the median from the true center as a function of sample size.  I wanted to make sure that I have acceptable sample sizes for my intended end-use of this approach.  I repeated the test ~3000 times per sample size setting and chose the median distance as representative.  In general the results for repeated tests to find the median on ~3000 runs had variation only in the 3d decimal place.  Here is the table of values of distance from the true center as a function of sample size.  samples err 10  2.008 15  1.676 20  1.456 25  1.317 30  1.198 35  1.124 50  0.930 90  0.698 100 0.659 300 0.386   I used  to try and determine the analytic form that is best described by the fit.  It looks like the following is the appropriate model.  AIC gives it as a decent candidate.    $$ Err(n) = \frac {6.5}{\sqrt{n}}$$  The domain is between 0 and 10 in x and y.  The value $ n $ is the number of samples.  Err is the distance between the median median and the true center.  Questions:   Can you confirm/reject that the general approach is correct based on the consistency between the median and the mean as a result from the code? Is the general form as spoken ground-up from the numbers as opposed to top-down by theory consistent with the textbook results from what the theory says it should be?  What is the appropriate expression there and how should it be derived? The denominator is expected, but where does the 6.5 in the numerator come from?  If my domain were a cube or a hypercube what should I expect of the numerator?   References and suggestions are always welcome.

If so, what? If not, why not?  For a sample on the line, the median minimizes the total absolute deviation. It would seem natural to extend the definition to R2, etc., but I've never seen it. But then, I've been out in left field for a long time.


I have a template class as follows.  template <typename KeyType> class Manager {   Manager(std::string name ); };  template<typename KeyType> Manager<keyType>::Manager(std::string name) {   //Do something; }   When I tried to create an object of this class, I am getting unresolved external symbol error. Anybody tell me what is the problem with my code.  std::string name; Manager<std::string> manager(name);

Quote from :     The only portable way of using templates at the moment is to implement them in header files by using inline functions.   Why is this?  (Clarification: header files are not the only portable solution. But they are the most convenient portable solution.)


We all hate the tags in the html page title, but they seem to be necessary for SEO: . Scraper sites used to destroy stackoverflow in the Google rankings.  However, as it looks like we're stuck with this, this seems like a prime candidate to remove for logged-in users.  This would do away with the annoying problem of having the tags in the title and would not affect the SEO rating, because Google would still see the same page as before and logged-in users would have a much nicer experience.

So, I see that  to fight site scrapers. But, this is harmful to User Experience. With browsers like Google Chrome, all I can see is the first few characters of the title, and it becomes annoying to try to find the right tab.  So, my request: Can you remove the tag from the <title> using JavaScript? Crawlers will still see the SEO-friendly <title>, and users won't have their user experience hampered by it. We all win.


I'm trying to create a simple reaction time (RT) task in javascript, and I'd like to have roughly 1 ms resolution. I've been testing some simple code to see if the distribution of RTs looks as expected. Basically, the script uses performance.now() to grab the time as soon as a key is pressed, and it compares that time to the previous key press time. In other words, I'm getting a simple distribution of times between keypresses.   To my surprise, the distribution was binned in 8ms intervals. For instance, there were peaks at roughly 120 ms, 128 ms, 136ms, etc. (decimal values are returned since I'm using performance.now()), but there were empty gaps in between. I've seen the exact same thing whether i'm using Firefox, Chrome, or Safari. What is causing this granular timing? Is this a limitation of my operating system, or of the browsers? Is there anything I can do to stop this binning and gain millisecond resolution? If it helps, I'm running OS X El Capitan on a 2012 Macbook Pro. Thanks!

Something that has always bugged me is how unpredictable the setTimeout() method in Javascript is.  In my experience, the timer is horribly inaccurate in a lot of situations. By inaccurate, I mean the actual delay time seems to vary by 250-500ms more or less. Although this isn't a huge amount of time, when using it to hide/show UI elements the time can be visibly noticeable.  Are there any tricks that can be done to ensure that setTimeout() performs accurately (without resorting to an external API) or is this a lost cause?


I have Windows 7 and use Microsoft Office Outlook 2006 and every time that I open it pops up a screen that says mobile me services has stopped working.    I use iCloud to merge my contacts and calendar from my iPhone 4S. What can I do to stop this from happening.  Should I uninstall iCloud and reinstall it?  What suggestions do you have?  I want to keep icloud.  If I delete mobile me will it delete icloud?

I keep getting the message MobileMe Service Stopped Working each time I open Outlook 2007. I have to click on the Close Program button in the error message twice each time it shows up while Outlook is trying to load up. Then I am able to use Outlook. I never use my iCloud account and would like to know how I can deactivate iCloud so I do not have issues with my Outlook.


In the image below, we can see ET's species at the bottom left. Is the species at the top right of the image known in Star Wars lore?

An answer , uses the appearance of E.T.-like creatures in the Star Wars universe as a frame of reference for dating the sagas relative to our present day.  I remember noticing, and discussing the E.T.-like creatures when I saw the film, too, but is there an in-universe explanation for this, or an in-universe tying of the two stories?    Or is it just a cute Hollywood nod on the part of Star Wars to the E.T. franchise?


Using the following SELECT Statement, I see all active drivers with a Credit Card Number : SELECT top 1000 * FROM cashcard WHERE crd_status = 'A'  Based on that query, I get a table with a bunch of columns. The column I'm focused on is the first one titled crd_cardnumber which is a list of credit card numbers that are associated with people that are active in our database. This is connected to our in-house database and we have an application that will run an automated query. I just need to create a SELECT statement that will return What has changed... in the crd_cardnumber column when I run it. Can anyone help me out?

Need help if anyone can offer! I currently have my select statement returning the TOP 1000 * results from a table. They are CC numbers that are currently active. I'd like to see how I can go about writing a query that could show me what has CC numbers have changed. If something has changed, it will send a report to the listed people. If nothing, then it does nothing. It only actions once something has happened. We have an inhouse system that will do the automated part... I just need a select statement that will return what has changed. If I can get some help on this, it would be amazing! Thank you!


I have recently switched from windows to ubuntu 14.0.1. Since I am a beginner, I have not much idea regarding ubuntu. I want to install some programs that I use in windows. I have the set ups but I am unable to install them in ubuntu. Please help.

Can .exe and .msi files (Windows software) be installed in Ubuntu?


$(document).ready(function () {     $(document).on('keydown', '.FIRSTNAME',         function (event) {             if (this.selectionStart == 0 && event.keyCode >= 65 && event.keyCode <= 90 && !(event.shiftKey) && !(event.ctrlKey) && !(event.metaKey) && !(event.altKey)) {                 var $t = $(this);                 event.preventDefault();                 var char = String.fromCharCode(event.keyCode);                 $t.val(char + $t.val().slice(this.selectionEnd));                 this.setSelectionRange(start, end);             }         }); });   can you use my code and edit it?  the difference is the first letter in every word...  I just want to capitalize the first letter in every word  someone help me... tnx in advance

Is there a simple way to convert a string to Title Case? E.g. john smith becomes John Smith. I'm not looking for something complicated like , just (hopefully) some kind of one- or two-liner.


I am struggling answering this question for myself: How can i prove that a Group $G$ is abelian, if $$g\circ g=e \ \forall g \in G $$  A group is abelian if this is true: $$a\circ b = b\circ a\ \forall a,b \in G$$ But i dont understand how to prove this.  Hope someone can help me out with this!

Possible Duplicate:             Let $(G,\star)$ be a group with identity element $e$ such that $a \star a = e$ for all $a \in G$. Prove that $G$ is abelian.   Ok, what i got is this: we want to prove that ab=ba, i.e. if aa=e , a=a' where a' is the inverse and bb=e, b=b' where b' is the inverse so ab=(ab)'=b'a'=ba....


I am struggling to understand the term static means and how it works. here I initialized a static variable "float percentage". and I have to convert it to percentage using convertToPercent() and after converting it I have to take the value and put the value to someMethod ()  to do some calculations  below is what I have   .h  class Foo     {  private:     static float percentage;  public :         float convertToPercent();  };   .cpp  float Foo::convertToPercent() {              percentage = (30/100) * 100;           return percentage; }  static float someMethod () {   //place the static percentage value here after doing convertToPercent() method to do some calculation; }   however it throws me an error message   Undefined symbols for architecture x86_64: "Foo::percentage", referenced from:  Foo::convertToPercent() in Foo.o   Apperciate for help given. thanks

What is the best way to initialize a private, static data member in C++?  I tried this in my header file, but it gives me weird linker errors:  class foo {     private:         static int i; };  int foo::i = 0;   I'm guessing this is because I can't initialize a private member from outside the class.  So what's the best way to do this?


I need to have a real map like the one attached, and I do some writing on it ??  Any suggestions please

Recently I have learned how to draw simple stuff with TikZ. I really like it. Now I wonder if it is possible to draw with TikZ on a image. Instead of pasting a image in Illustrator and adding some vectors to point something in the picture I would like to do it using TikZ. Is it possible?   For example, on a picture of a computer (PNG,etc) I would like to draw some arrows and labels saying "Keyboard", "Monitor", etc.


I am overlaying some WGS84 (EPSG:4326) coordinates over a few DEM rasters with EPSG:102710 (NAD_1983_STATEPLANE_NEW_HAMPSHIRE_FIPS_2800_FEET)  When they are these two different layer CRS the coordinates overlay perfectly where they are supposed to be, however, if I change the coordinates to have the same EPSG as the DEM rasters, then the coordinates are way off. What is the explanation for this?  The rasters were from this site: . "Digital Elevation Model - Quad 54" for example.   Unfortunately, I cannot provide the coordinates.

I put 4 different layers into my ArcMap document, but only one of them will show up on the map! I should be seeing the other 3 layers as well. When I do a Zoom to layer, I can see one layer, but I cannot figure out how to make the other 3 show up at once on top of each other.  Before I opened ArcMap, I used ArcCatalog where I right-clicked 3/4 of the shapefiles and  clicked Properties → Coordinate system → Import and then clicked on my Trees layer, which has the coordinate system I want the other 3 to have. But when I opened ArcMap the 4 layers did not overlap, nor could I move them above or below each other.


I was successfully using UBUNTU for a while until after a silly mistake I deleted some files. I had the system running together with my Windows but now I cannot reboot in Ubuntu, it gives me an error message and says that some files are missing :(  Is there a way I can uninstall Ubuntu from within Windows?    Or can I just install the same version of UBUNTU? would the two systems not collide?

I have absolutely no experience with Linux, and I desperately need to get my computer back up and running again with Windows.  How do I remove Ubuntu and reinstall Windows?    Editor's note: many of the answers are about removing Ubuntu from dual-boot but keeping Windows (which is a bit complicated), while other answers are about removing Ubuntu from single-boot (which is easy: basically just format the disk while installing Windows). The question as written is ambiguous between dual-boot or single-boot.


I'm stuck at 99.3% in Stranger Things The Game and I don't know what to do.   I have followed the tutorial on how to do it but I must be missing something.  How can I complete the missing 0.7%

I have completed every level and every quest (that I know of) in the game, but I am only at 98.7% complete.  I have found all 8 Eggos, all 8 VHS tapes, all 12 garden gnomes, and all 40 heart pieces. I've unlocked Eleven and watched the movie in the Hawk Theater.  In my inventory, I have 3 backpacks, an aluminum bat, a D-cell flashlight, a Canadian tuxedo, a 20-sided die, a spiked club, and a Ghostbusters lunchbox. I also have the hazmat suit, dynamite, flowers, and the key, but those are all required to complete the game anyway. There are no quest items remaining and I've talked to everyone in the game.  What am I missing?  I'm playing on hard if that makes a difference.


Many Mac apps have "hidden" configurable options that can be modified in Terminal by using the defaults write ... command. This is straightforward to do if you know the name of the option that you want to configure ahead of time.  Is a list of values that each application actually uses tucked away somewhere in a master config file?   How do people discover these options without a list of all configurable options for a given Application?

I want to know all keys (property list) which available on certain domain application, as example I could list available key for com.apple.dock by entering this command:  $ defaults read com.apple.dock   but somehow the output of this command only showed the active property list key, and yet not all available key for com.apple.dock listed there.  Anyone can help me on this?


I have requirement like to display related records related to leads with sic code starts with.So i filtered with using Like operator but i am getting exception 101 exception.But i am not able to bulkify below code.  how to handle in this case.      public class LeadController      {         public String CurrentId;         public List<Opportunity> newopplist{get;set;}         public List<Opportunity> listopp{get;set;}          public LeadController(ApexPages.StandardController controller) {          CurrentId=ApexPages.currentPage().getParameters().get('id');         }          public void search()         {             set<String> cityset=new set<String>();             Map<String,String> citymap=new Map<String,String>();             Map<String,String> statemap=new Map<String,String>();             Map<String,String> Siccodes=new Map<String,String>();             List<Opportunity> newopplist=new List<Opportunity>();             for(Lead ld:[Select Id,City,State,SIC_Code_1__c from Lead where Id=:CurrentId ])             {                 // cityset.add(ld.City);                 if(ld.City <> null)                 {                     citymap.put(ld.City,ld.City);                 }                 if(ld.state <> null)                 {                     statemap.put(ld.State,ld.State);                 }                 if(ld.SIC_Code_1__c <> null)                 {                 Siccodes.put(ld.SIC_Code_1__c, ld.SIC_Code_1__c);                 }             }             newopplist=[Select Id,Name,Account.name,Number_of_Units__c,StageName,account.SIC_Code__c,Type,                         Billing_City__c,Billing_State_Province__c,account.SIC_Industry_Name__c,                         account.No_of_active_units__c from Opportunity where StageName='Closed Won' ];             listopp=new List<Opportunity>();             for(Opportunity opp: newopplist)             {                           if(!Siccodes.isEmpty())                 {                     Set<String> codes = new Set<String>();                     for(String code:Siccodes.keySet())                     {                         codes.add(code + '%');                     }                     listopp=[Select Id,Name,StageName,Account.name,Number_of_Units__c,account.SIC_Code__c,Type,                              Billing_City__c,Billing_State_Province__c,account.SIC_Industry_Name__c,                              account.No_of_active_units__c from Opportunity where account.SIC_Code__c                               LIKE :codes and StageName='Closed Won' ORDER BY account.No_of_active_units__c Desc Limit 10];                                      }        } }   I am hitting limits because of this query as per debug logs.     Select   Id,Name,StageName,Account.name,Number_of_Units__c,account.SIC_Code__c,Type,                                    Billing_City__c,Billing_State_Province__c,account.SIC_Industry_Name__c,                                    account.No_of_active_units__c from Opportunity where account.SIC_Code__c                                     LIKE :codes and StageName='Closed Won' ORDER BY account.No_of_active_units__c Desc Limit 10

A general question asked from time to time on stack exchange is question of trigger bulkification.  Therefore I have 2 questions:   Which best practices are you using? What is the best way to handle updates of more than 200 records? (In case of more than 200 records the trigger is executed more than once.)


When Thanos and his army attacked Avengers HQ in Avengers: Endgame, E.D.I.T.H. was in existence because Tony   died in the battle  so he couldn't build it after the battle. Why didn't he use E.D.I.T.H. in the battle? I know that E.D.I.T.H. stands for Even Dead, I'm The Hero. It means that Tony built it to gift it to someone else through his will. But, Thanos' attack was an emergency situation. E.D.I.T.H.'s drones and missiles with coordinated intelligence could certainly prove useful against Thanos and his army. Why didn't Tony use E.D.I.T.H.?

In Spider-Man: Far From Home, we see that Tony Stark      has left behind an augmented reality security, defense and artificial tactical intelligence system for Peter, called E.D.I.T.H (Even Dead, I'm The Hero).   And as we see further in the movie, quoting from ,      [E.D.I.T.H] allows the user full access to the entire Stark satellite network, which comes with several hundred tactical drones.   Following , it can be assumed that E.D.I.T.H was probably       developed by Stark during the five years time after the snap. The drone network could have been also put in place during the same time as well (otherwise, when could he?).   Considering this, is there a reason why, in Avengers: Endgame Tony didn't think of using      the drone network during the final battle at the Avengers HQ against Thanos and his army?


I know it has been asked before, but I'm still not sure if I understand the focal length issues of EF-lenses on APSC cameras in Canon system. I already have the EF-S 55-250 IS STM and I'd like to buy a longer telephoto - if I get the EF 70-200 will it give me effectively more range than EF-S 55-250 (200 x 1.6 = 320 mm)?

I have a Canon 7D, which has a crop factor of 1.6x.  When using a Canon EF-S lens I get the focal length stated on the lens, when using a Canon EF lens I get the focal length times 1.6 when used on the APS-C body. At least that's what I thought.  I just compared two lenses:   Canon EF-S 15-85mm f3.5-5.6 Canon EF 70-200mm f4   .  The top photo is shot with the 15-85, the bottom photo with the 70-200 - both lenses are set to 70mm. Now why do they look the same?  I thought I would get 112-320mm (70mm*1.6 crop factor). What did I misunderstand about the crop factor calculation? Lightroom also displays the photos as having "70mm" and not 112mm.


A function on a set $X$ to a set $Y$ is order preserving (monotone, isotone) Consequently, one cannot expect that the inverse of a one-to-one order preserving function will always be order preserving. However, if $X$ and $Y$ are chains and $f$ is one-to-one and isotone, then necessarily $f^-$ is isotone.   In this excerpt, taken from General Topology by John Kelley, the author asserts the inverse of an one-to-one isotone function need not be isotone.  How did the author conclude that?   I would appreciate an illustration that might help me visualise what author meant to say.

Suppose $\left(A,\leq_{A}\right)$   and $\left(B,\leq_{B}\right)$   are Posets and $f:A\to B$   is an order preserving bijection. I'm trying to show that $f^{-1}:B\to A$   is also order preserving. That is I want to show that given $b_{1},b_{2}\in B$   $$b_{1}\leq_{B}b_{2}\Longrightarrow f^{-1}\left(b_{1}\right)\leq_{A}f^{-1}\left(b_{2}\right)$$  Since $f$   is bijective there are uniquely defined $a_{1},a_{2}\in A$   such that $$b_{1}=f\left(a_{1}\right)\Longrightarrow a_{1}=f^{-1}\left(b_{1}\right)$$ $$b_{2}=f\left(a_{2}\right)\Longrightarrow a_{2}=f^{-1}\left(b_{2}\right)$$  If $a_{1},a_{2}$   are comparable and I assume $a_{2}\leq_{A}a_{1}$   I get a contradiction since $f$   is order preserving: $$b_{2}=f\left(a_{2}\right)\leq_{B}\, f\left(a_{1}\right)=b_{1}$$  So I deduce that if $a_{1},a_{2}$   are comparable then necessarily the required inequality holds. My question is whether it's possible that $a_{1},a_{2}$   are not comparable and the claim is actually false?


Sorry if this is perhaps a duplicate of an already answered question. I am very curious of the purpose of being blocked from deleting answers after the limit of 5 daily deletions have been reached?

I was improving some of my old posts on Stack Overflow when I ended up encountering this:     You have already edited 5 of your own post today; futher edits are not   allowed until tomorrow   I know this it is not a major deal, but what's the logic underneath to this restriction?


How to prove that field inside a hollow sphere is zero anywhere inside that sphere using solid angle concept?

It is quite easy to derive the gravitational field intensity at a point within a hollow sphere. However, the result is quite surprising. The field intensity at any point within a hollow sphere is zero.   What exactly is the reason behind this? Except for, of course, the mathematics behind it. Is there any logic why the field intensity should be zero within a sphere? For example, it is logical to say that the field intensity would be zero at the center, as all the intensities cancel out. However, this cannot be the case for any point within the sphere.


This was in a sample/preview chapter from another book that the publisher included at the end of something else, so I don't have much to go on, but here are the elements I recall -   the characters lived in free fall in open space, with no need of environment suits. everything was in orbit around a very small sun, not very far away.  unclear if breathable atmosphere extended to the sun, or was confined to a ring.  the level of technology at hand seemed to be pre-industrial. the physical constants of the universe were different so that such a small sun could exist. material resources were running out, which seemed to imply the necessity of interstellar travel. I dimly recall something about coal or carbon being prominent.   The setup is similar in some respects to Larry Niven's Integral Trees, but it's definitely not that. In Integral Trees, the habitable spaces was a gas torus around some kind of ordinary collapsed star, but in this unknown work, the system center was a miniature sun which required a physically different universe altogether.  I'd like to read it, but I'm not sure I even still have the paperback that had that preview in it. Name that book, please!

I read this story online, maybe 2 years ago. It was about a group of people (the size of a village IIRC) who somehow got transported to another universe, where the gravitational constant was orders of magnitude higher than ours.  The funky consequences of this were explored in the story -- I remember a scene where someone put their hand near a local lifeform to feel its gravitational field. Stars were much smaller and shorter lived due to the dramatically increased gravity. The people lived on a "lifeboat" in orbit around a star, which IIRC was a few km across and had a lifespan of a few years. A major plot point was the fact that they needed to move to another star, because theirs was nearing the end of its lifespan. In the end, they succeed to do just this.


This is a concept I don't fully understand. If I have two photons each with frequency $\nu$, then they each have an energy of $E = h\nu$. If they get matched with an inverted phase, then the summed wave will be null due to destructive interference. Then where does the energy go? It cannot radiate, since that would produce an extra E-M wave, right?

What happens to the energy when waves perfectly cancel each other (destructive interference)? It appears that the energy "disappear" but the law of conservation of energy states that it can't be destructed. My guess is that the kinetic energy is transformed into potential energy. Or maybe it depends on the context of the waves where do the energy goes? Can someone elaborate on that or correct me if I'm wrong?


In QGIS, I can use the identify tool to get the pixel value and the coordinate for a selected pixel, I also have a coordinate capture tool to display the selected pixel in another coordinate system.  But how can I display the row/column of this particular pixel, which x and y of the total dimension this pixel is located at?

Is it possible in QGIS to display column and row index of pixel in raster?   I mean something similar to value tool.


Is it possible to simultaneously connect two pairs of AirPods with my Apple Watch (series 3)? This would allow me and someone else to listen to the same music, podcast, Audible book, etc.

I would like to pair two sticky dude Bluetooth speakers, at one time with my iPhone. With two of them at once it would be like stereo sound. Is there an app or something maybe?


How can I typeset a simple diagram (dividend-quotient-remainder) in a base different to decimal? For example: $120101_{3} \div 102_{3}$

I am teaching how to convert from one base to another base, however, I can't find a way to do something like this:    I know little about Tikz, the only thing I have been able to produce is a simple square with a couple of lines over it, so I don't even know where to start. Any suggestions? I don't mind typing all the numbers, what I want to do is to automatize the process of creating the lines.


Does there exist a continuous positive function such that $\int\limits_1^{\infty}f(x)dx$ converges, while $\int\limits_1^{\infty}f^2(x)dx$ diverges? I have proved that if $f$ is decreasing monotonically, then this is false and $\int\limits_1^{\infty}f^2(x)dx$, but what happens when the demand for monotonic drops?

I'm trying to find an example of a continuous function $f:[1,\infty) \to \Bbb R $ such that  $$f(x) >0 $$  $$\int_{1}^{\infty} f(x) \ dx \ \text{converges and } \int_{1} ^{\infty} f(x)^2 dx \ \text{diverges}.$$


I'm confused about when to use ourselves and when to use us. I looked at , but I'm not sure how to generalize that answer to the sentence I am working with.     We need to base our judgments about how safely people will act toward ourselves and our children on how well we know them and their behavior in the moment.   My inclination is to tell the author to change ourselves to us. Is that correct?     We need to base our judgments about how safely people will act toward us and our children on how well we know them and their behavior in the moment.    In the sentence, we refers to parents in general as a whole in society.

I'm confused by why people use the following:     It's up to yourself.   Rather than:     It's up to you.   Another example of this would be:     Please feel free to contact ourselves if you have any problems.   Rather than:     Please feel free to contact us if you have any problems.   Are both of these correct?  Is there any reason for using the former?


I'm developing a web-application for iPhone and Android. It works flawlessly on the iPhone but when I try to run it on an Android device, it just does not work.  But to the point… I need to access the (JavaScript) error console in the Android default browser. Is there a way to do that?  I tried changing the "Enable tracing" setting after accessing the hidden about:debug menu in the browser but nothing seems to change.  UPDATE: by the way, I'm using the Android Virtual Device software from the Android SDK.

I'm developing a JavaScript application that needs to run on the Google Android Phone OS.  Is there a way to enable the JavaScript Error/Debug console within Safari on either the Android Emulator or an actual device?  If so any instructions on how to do so would be appreciated.


I am very new to Ubuntu and am pretty much using it as a refuge from Windows 10.   This being said I really have no prior knowledge in Ubuntu or anything computer related. I've had this problem for a while now, and it's almost definitely user error, I know, where I can't download anything from software center because it says the packages are untrusted (I have looked into some of the other threads that answer this question, none of them seem to work), and when I hit okay when the popup appears, the installation stops completely, so when I hit repair the popup re-opens repeatedly and it seems to install a whole lot of packages that I guess just decide to not exist.  You've probably guessed by now that I... am bad with computers. Please help

It didn't fixed the error. So, how do I fix my GUI update?  For every software I have to install it from command line because I got same error when install software from Ubuntu Software Center.


I have Ubuntu 14 running in vmware but I want to make the desktop look like Windows 7. I tried  sudo apt-get install xubuntu-desktop   but when logged out I can't see xfce session.  I also tried  sudo add-apt-repository ppa:upubuntu-com/gtk3  sudo apt-get update  sudo apt-get install win2-7  gsettings set org.gnome.desktop.wm.preferences theme 'Win2-7-theme'  gsettings set org.gnome.desktop.wm.preferences button-layout 'menu:minimize,maximize,close'    to no avail.

I'm totally new to Ubuntu. I've installed version 16.04 and I'm having trouble finding my way around. I've tried just about all possible ways to make Ubuntu look like windows 7. Every way I tried was missing something, Is there a way to make version 16.04 be like win7?


The problem is $$\int \cos^3 (x)  \sin^5 (x) dx.$$  The method we've gone over in class involes splitting up the trig functions so that we can set one to U, then take du so that du matches a part of the function. But I'm struggling to find these. Any explanation is helpful.

Suppose $\displaystyle P(x,y)$ a polynomial in the variables $x,y$.   For example, $\displaystyle x^4$ or $\displaystyle x^3y^2 + 3xy + 1$.  Is there a general method which allows us to evaluate the indefinite integral     $$ \int P(\sin x, \cos x) \text{d} x$$   What about the case when $\displaystyle P(x,y)$ is a rational function (i.e. a ratio of two polynomials)?   Example of a rational function: $\displaystyle \frac{x^2y + y^3}{x+y}$.    This is being asked in an effort to cut down on duplicates, see here:   and here:


I'm getting an index out of bounds exception in a toy project I made to follow a tutorial. The loop is supposed to start a bunch of tasks and store the Task objects in an array. After the for loop finishes I await the tasks using Task.WhenAll() and print the result. The loop is supposed to terminate when i < Pages.Length == false, but the out of bounds error is being thrown when i == Pages.Length (after the loop should have terminated).  My main question is: Why is the variable i being allowed to reach Pages.Length?  This seems to be an extremely common loop, so any insight into this would be greatly appreciated.  (The loop in question is the topmost loop on line 6)          private async void AsyncClick(object sender, RoutedEventArgs e)         {             Stopwatch watch = Stopwatch.StartNew();             Task<WebPageData>[] tasks = new Task<WebPageData>[Pages.Length];             ConsoleOutput = $"Starting Download {Environment.NewLine}";             for (int i = 0; i < Pages.Length; i++)             {                 tasks[i] = Task.Run(() => DownloadPage(Pages[i]));             }              WebPageData[] results = await Task.WhenAll(tasks);              for (int i = 0; i < tasks.Length; i++)             {                 ConsoleOutput += $"{results[i].URL} : The length is {results[i].PageContents.Length}{Environment.NewLine}";             }              watch.Stop();             ConsoleOutput += $"Finished downloading in time: {watch.ElapsedMilliseconds} ms";         }           private WebPageData DownloadPage(string websiteUrl)         {             WebClient client = new WebClient();             WebPageData data = new WebPageData() { URL = websiteUrl };              data.PageContents = client.DownloadString(data.URL);             return data;         }    As the code is the debugger throws an error when i == Pages.Length == 3.  I've tried changing i < Pages.Length to i < Pages.Length - 1, which result in the loop being finished, but a null exception later in the code (expected).  I've also tried putting in if(i >= Pages.Length) break into the loop, but it had no effect for some reason.

I met an interesting issue about C#. I have code like below.  List<Func<int>> actions = new List<Func<int>>();  int variable = 0; while (variable < 5) {     actions.Add(() => variable * 2);     ++ variable; }  foreach (var act in actions) {     Console.WriteLine(act.Invoke()); }   I expect it to output 0, 2, 4, 6, 8. However, it actually outputs five 10s.  It seems that it is due to all actions referring to one captured variable. As a result, when they get invoked, they all have same output.  Is there a way to work round this limit to have each action instance have its own captured variable?


I've never seen a capacitor that looks like this, and I known blown ones are either in pieces or typically bulging. This looks like compound I've seen on CRT rings and pots, put there by the factory to show something has been calibrated and not moved since, but why would they put it on a cap like this? Just to show it's original?    I'm assuming of course that I'm not way off base and this cap is blown. This is a 100V power board that I'm reasonably sure has been connected to a 220V source at some point, the fuse to the left is clearly blown.

I'm not an engineer, but my monitor stopped working yesterday (it just wouldn't display anything but still gets power) so I figured I'd like to take it apart and see what went wrong.  At the very least I'd get to see what the inside of a monitor looks like :).  Anyway, I took it apart, and also read around about my issue and it seems the capacitors have gone bad, at least some of them.  However, I also noticed some white elastic stuff all over the board.  Some of them are sticking two capacitors together and to the board, but I also see some from where power socket connects to the board.  My question is, what is the white stuff?  Should I replace all capacitors that have white stuff around it, and should I also replace the power socket part?  Or should I just replace the bulging capacitors and leave it at that?  UPDATE:


I'm interested in learning about the basics of group theory. My background is in statistics so I have barely any knowledge about group theory. I've had some work with proofs and I have also taken classes at university such as multivariable calculus, linear algebra, and differential equations. Any beginner resource would be helpful but nothing too technical.

Which textbook is good for introductory group theory?


As is well known, the gravitational force between two masses is dependent on the spatial distance between them. Therefore, even at vast distances, the masses exert equal and opposite forces on one another. I know that our theories need for this to be the case (to derive things such as escape velocity, which calls the force at r = $\infty$ to be zero (by utilizing a limit where the distance approaches infinity)), yet the universe is so vast and complex (with an unimaginable number of masses). With so many masses in space, it seems as though this could make a huge difference (over a large distance, such as special relativity's involvement in magnetism) .  Also, say there is a supernova 400 light years away from earth. The time independent theory states that we should immediately notice a difference in the net forces acting on us, yet that would mean information travelled faster than light, correct?  My main point is this: Is it absolutely imperative that there is still a force infinitely far away? Would the universe still function if we were to cut it off at something like a light year? *(This is my main point) Does the infinite reach of the gravitational force have anything to do with the scaffolding of the universe as a whole ?

A thought experiment: Imagine the Sun is suddenly removed. We wouldn't notice a difference for 8 minutes, because that's how long light takes to get from the Sun's surface to Earth.   However, what about the Sun's gravitational effect? If gravity propagates at the speed of light, for 8 minutes the Earth will continue to follow an orbit around nothing. If however, gravity is due to a distortion of spacetime, this distortion will cease to exist as soon as the mass is removed, thus the Earth will leave through the orbit tangent, so we could observe the Sun's disappearance more quickly.  What is the state of the research around such a thought experiment? Can this be inferred from observation?


I am learning Statistics as a prerequisite for Data Science course. I would like to know the difference between Correlation and Regression with an example.   Could someone help me please ?

In particular, I am referring to the Pearson product-moment correlation coefficient.


I run fix installation command after which terminal removed all the files and now it is showing this black screen.  How can I repair my system?

I am trying to boot Ubuntu on my computer.  When I boot Ubuntu, it boots to a black screen.  How can I fix this? Table of Contents:


I have read other answers to try to find the solution but nothing clearly explains the issue.   Why should the following code block create a null pointer exception for currArraySize?      int biggestArraySize = 0;    int currArraySize = 0;     for(int i = 0 ; i < myMap.keySet().size(); i++){         ArrayList<String> currList = new ArrayList<String>();        currList =  myMap.get(i);        currArraySize = currList.size();         if(currArraySize > biggestArraySize){          biggestArraySize = currArraySize;          }      }       System.out.println(biggestArraySize);

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


I refer to the questions at  and   My question may be a duplicate, but the answer given in the first of those questions will not resolve the issue I am experiencing. If the CRS thing from the second one is a more likely cause, I would like a clear explanation.  I am using Windows 8.0 and the CRS of my map is EPSG 27700  It happens most often when I select my label, but it can be after selecting other items. Everything freezes on the layout - the selection pointer has no effect. I can add new items, but I can't move them or select anything else. I can select all or deselect all using the menu command, but still the pointer has no effect when clicked on the layout. I can lock and unlock using toolbar buttons, but not with a right click. I can use toolbar buttons to send selected items to back or front, but it makes no difference to the lack of pointer click functionality.  If I open a new print composer from my template, or if I close and re-open QGIS, the composer may work ok for a while, but then the same thing happens again. It was more intermittent, but today it is happening almost immediately every time.  I have disabled all my plug-ins, but it made no difference.

I am having an issue where I can create a print Layout in Print Composer, but once I have clicked away from an item (like map, legend, arrow, etc) I cannot select it again.


I have an idea that I would like to publish. However, the idea is so simple that basically everyone in the field could reproduce the experiment that shows its benefit within a day or so.  What can I do to ensure that my idea is not stolen during the review process by a reviewer, for example?  If the reviewer holds back my paper and publishes it himself somewhere else, is there something I can do to prevent this?

Suppose some author provides his original research article to a journal for publication. In this way, he is disclosing or revealing his confidential research work to that journal. Now, consider the case that his article gets rejected. So, is it not possible that whoever reviews that article can publish that kind of work and say that it's theirs? Since the original author's work has not been published and he is disclosing his confidential work to somebody, how could the author get assurance that if his article is rejected, his work will not be leaked by the journal staff in any form? What happens if this kind of thing happens?


For me, multiplication is a binary operation so it can be applied only on a finite sequence of numbers. but $1^{\infty}$ requires that we apply multiplication infinitly which is not defined as multiplication is a binary operation.  Is that a good reason? If not, what is the reason?   If my reason is ok, So similarly, $5^{\infty}$ is indeterminate ?   ِAdded:   I noticed that all answers are in context of "limits". Algebraically, multiplication is a binary operation, So it ONLY can be used to define multiplication of finite sequence of numbers as not a infinite sequence. So algebraically, what does $1^{\infty}$ even mean?

From : In calculus and other branches of mathematical analysis, an indeterminate form is an algebraic expression obtained in the context of limits. Limits involving algebraic operations are often performed by replacing subexpressions by their limits; if the expression obtained after this substitution does not give enough information to determine the original limit, it is known as an indeterminate form.    The indeterminate forms include $0^{0},\frac{0}{0},(\infty - \infty),1^{\infty}, \ \text{etc}\cdots$   My question is can anyone give me a nice explanation of why $1^{\infty}$ is considered to be an indeterminate form? Because, i don't see any justification of this fact. I am still perplexed.


I am studying Algebraic Topology and increasingly find that when I turn to the internet for help, the explanations and even definitions I need are given in terms of Category Theory (which I know nothing about).  This seems to be true especially for the algebraic, but also the topological, aspects of the topic. (The sites I consult most are Wikipedia and Wolfram.)  My question is this: Is an understanding of Category Theory becoming a prerequisite for a good understaning of Algebraic Topology?  If so, I would appreciate any suggestions concerning sources on Category Theory relevant for studying Algebraic Topology (rather than for studying Category Theory, per se).

First my question:     How much category theory should someone studying algebraic topology generally know?   Motivation: I am taking my first graduate course in algebraic topology next semester, and, up to this point, I have never taken the time to learn any category theory. I've read that category theory helps one to understand the underlying structure of the subject and that it was developed by those studying algebraic topology. Since I do not know the exact content which will be covered in this course, I am trying to find out what amount of category theory someone studying algebraic topology should generally know.  My university has a very general outline for what the course could include, so, to narrow the question a bit, I will give the list of possible topics for the course.   Possible Topics:   unstable homotopy theory  spectra bordism theory cohomology of groups localization rational homotopy theory differential topology spectral sequences K-theory model categories   All in all, I am well overdue to learn the language of categories, so this question is really about how much category theory one needs in day to day life in the field.   Update  I emailed the professor teaching the course and he said he hopes to cover the following (though maybe it is too much):   homotopy, homotopy equivalences, mapping cones, mapping cylinders fibrations and cofibrations, and homotopy groups, and long exact homotopy sequences.  classifing spaces of groups. Freudenthal theorem, the Hurewicz and the Whitehead theorem. Eilenberg-MacLane spaces and Postnikov towers.  homology and cohomology theories defined by spectra.


How do you prove ${\lim\limits_{m \to +\infty}} \ln{\left(1+\frac{r}{m}\right)} = \frac{r}{m}$, where $0 < r < 1$?  I encountered this problem while trying to reproduce the third to last step in this .

$$\lim_{x\to 0} \frac{\ln(1+x)}x$$  The process I  want to take to solving this is by using the definition of the limit, but I am getting confused. ( without l'hopitals rule)   $$\lim_{h \to 0} \frac{f(x+h) - f(x)}h$$  $$\lim_{h \to 0} \frac{\frac{\ln (1+x+h)}{x+h} - \frac{\ln(1+x)}x}h$$  $$\lim_{h \to 0} \frac{x\ln(1+x+h) - (x+h)\ln (1+x)}{hx(x+h))}$$  At this point I get confused because I know the answer is $1$, but I am not getting this answer through simplification of my formula.


Are there any settings concerning the connection to the Windows Store?   I find I cannot connect to it after refreshing my computer. I got the following message for two days. I don't think Windows Store is down, so there must be something wrong.   My internet connection is working fine. I can also use the Game store, Bing and anything else, but just can not connect to the Windows Store.

After upgrading Windows 8 Enterprise to Windows 8.1 Enterprise (RTM), the store app won't launch anymore, hanging on the splash screen forever. Is there a trick to reset the store app or something? Restarting or killing the app didn't work. There are no error messages in the event logs (TWinUI/Operational etc.).


This is the code that I've written to remove spaces in the given string. It normally works.    string a = "hello  there world";    int n = a.size();    for(int i =0 ;i<n;++i){        if(a[i] == ' '){            a.erase(a.begin()+i);        }    }    cout<<a;  But for the given input above ( note that there are two spaces between "hello" and "there" ), my output is:  hello thereworld  "hello" and "world" still have a single space between them. Is this behaviour normal? Is it something to do with erase ?

What is the preferred way to remove spaces from a string in C++? I could loop through all the characters and build a new string, but is there a better way?


Can you please explain the grammar behind the use of the article "a" in the following sentence, as you would explain it to an English language learner?  Teresa, from the Hubbs-Sea World Research Institute, tries to keep a shivering, injured Winter warm and calm.   (p.s. Winter is the injured dolphin's name)  Thank you so much!

Two years after his reported Reichenbach Fall demise, Sherlock, who has been cleared of all fraud charges against him, returns with Mycroft's help to a London under threat of terrorist attack.    I know, there are  (like The Hague), but I've never heard someone say a London till now.  Is a London under threat of terrorist attack used here as a description of some indefinite place in London?


I just studied Munkres, but there is only one line that box topology is finer no any explaination. I think i just need to show tha basis elements of box topology are contained in the basis element of product topology but i don't know how??

I am having a hard time understanding why the box topology is finer the the product topology. Of course I know that with finite product, the two are the same. With product topology, the basis elements are defined so that the $U_{\alpha}=X_\alpha$ except for finitely many $\alpha$. So how can this topology be contained in the box topology which has only the product of the  $U_{\alpha}$ as basis. I think it should have been the other way round. Am I missing something here? I need help with this because I have been confused over it for a long time.


i am getting java.lang.NullPointerException error at following line  in both files Base file and HomePage file at following line code  driver.manage().timeouts().implicitlyWait(10, TimeUnit.SECONDS); and  driver.get("");  Base class public class Base {      public WebDriver driver ;      public WebDriver InitializeDriver() throws IOException     {         Properties Prop =new Properties();          FileInputStream fis=new FileInputStream("C:\\Users\\Raj\\eclipse-workspace\\MavenSelenium\\src\\main\\java\\FirstMaven\\MavenSelenium\\Data.properties");          Prop.load(fis);         String browsername = Prop.getProperty("browser");          if (browsername=="Chrome")         {             System.setProperty("webdriver.chrome.driver", "C:\\Users\\Raj\\eclipse-workspace\\Work\\chromedriver.exe");             driver=new ChromeDriver();         }         else if (browsername=="Firefox")         {            System.setProperty("webdriver.chrome.driver", "C:\\Users\\Raj\\eclipse-workspace\\Work\\geckodriver.exe");            driver=new FirefoxDriver();           }         else if(browsername=="IE")         {             System.setProperty("webdriver.chrome.driver", "C:\\Users\\Raj\\eclipse-workspace\\Work\\IEDriverServer.exe");             driver=new InternetExplorerDriver();         }         driver.manage().timeouts().implicitlyWait(10, TimeUnit.SECONDS);         return driver;     }   }  and HomePAge Class  public class HomePage extends Base{  @Test public void Navigation() throws IOException {  driver=InitializeDriver(); driver.get("https://www.google.com");  }      }

What are Null Pointer Exceptions (java.lang.NullPointerException) and what causes them?  What methods/tools can be used to determine the cause so that you stop the exception from causing the program to terminate prematurely?


I am curious if there is a way to get the vertex of a parabola without calculus?  I know the calculus approach has you take the derivative set to $0$ (for $0$ slope) so if $f(x) = ax^2 + bx + c$ then $f'(x) = 2x + b$ so $0 = 2x + b$ implies $x = -\frac{b}{2a}$ with $y$ coordinate $f(-\frac{b}{2a})$.  But how would we get the vertex without calculus?

I'm taking a course on Basic Conic Sections, and one of the ones we are discussing is of a parabola of the form  $$y = a x^2 + b x + c$$  My teacher gave me the formula:  $$x = -\frac{b}{2a}$$  as the $x$ coordinate of the vertex.  I asked her why, and she told me not to tell her how to do her job.  My smart friend mumbled something about it involving calculus, but I've always found him a rather odd fellow and I doubt I'd be able to understand a solution involving calculus, because I have no background in it.  If you use something you know from calculus, explain it to someone who has no background in it.  Because I sure don't.  Is there a purely algebraic or geometrical yet elegant derivation for the $x$ coordinate of a parabola of the above form?


Find an irrational $n$ such that $n^n$ is a rational number.   I have some tries to find this... I have tried so much numbers but no success. How can I find them.

It can be proved that there are two irrational numbers $a$ and $b$ such that $a^b$ is rational (see ) and that for each irrational number $c$ there exists another irrational number $d$ such that $c^d$ is rational (see ).  My question is: Is there an irrational number $a$ such that $a^a$ is rational (and how could you prove that)?


.search JS method seems to want a string literal not a variable…   for (app in Servers) {     the_name = Servers [app]["Name"];     the_app = Servers [app]["App Name"];     search_str = "/"+Name+"/";     hit = the_app.search(search_str);     if (the_name == Name || the_app == "Foo Bar" )     {         result.Index = app;       } }   I want to generate a hit for a set of Apps that have a common Word for e.g. Name = "Skittles" will hit on Apps where app_name == "Skittles 1.0"; "Skittles 1.5"; "Skittles 3.2 — The Deluxe Edition 3.2"; etc etc  Name is a user definable variable. Servers is an object made available to me that lists video servers I can stream from running on my machine, each item in Servers will correspond to a server and have a "Name" item and a "App Name" item in it's object. (It's  thing this is not an HTML/web context).   Should I look at using a different method to construct the regexp?

I would like to create a String.replaceAll() method in JavaScript and I'm thinking that using a regex would be most terse way to do it.  However, I can't figure out how to pass a variable in to a regex.  I can do this already which will replace all the instances of "B" with "A".  "ABABAB".replace(/B/g, "A");   But I want to do something like this:  String.prototype.replaceAll = function(replaceThis, withThis) {     this.replace(/replaceThis/g, withThis); };   But obviously this will only replace the text "replaceThis"...so how do I pass this variable in to my regex string?