The ' grub-efi-amd64-signed' package failed to install into / target/.   Without the GRUB boot loader, the installed system will not boot.   This is the error I get every time I try to install 18.04. I have formatted the MBR and C drive of Windows and currently I have only dev/sda to install. I don't want to lose other data which I had in Windows 10.   What should be the status of legacy mode and secure boot while installing Ubuntu 18.04?  I see only dev/sda instead of dev/sda2, dev/sda3.  What should I do?

I have Dell Inspiron 5567 laptop (i-7, 8GB) with Windows-10 OS installed on it. I am trying to install ubuntu 16.04 as a dual boot OS on Windows10. I have disabled fast boot and secure boot options also. I am facing this error while installing Ubuntu 16.04:  grub-efi-amd64-signed failed to install into /target/. Without GRUB boot loader, the installed system will not boot  The target partition is /dev/sda1.  I have created three partitions:  20GB-ext4- Root mounted 18.9GB-ext4- /home 4GB Swap area   Launchpad link for the log files:   Pastebin link for boot-repair:   Output of sudo fdisk -l:   Disk /dev/sda: 931.5 GiB, 1000204886016 bytes, 1953525168 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 4096 bytes Disklabel type: gpt Disk identifier: F87D48DF-F3FF-429E-8F0B-558F81712A60  Device          Start        End    Sectors   Size Type /dev/sda1        2048    1026047    1024000   500M EFI System /dev/sda2     1026048    1288191     262144   128M Microsoft reserved /dev/sda3     1288192 1843265535 1841977344 878.3G Microsoft basic data /dev/sda4  1927151616 1928073215     921600   450M Windows recovery environment /dev/sda5  1928073216 1951281151   23207936  11.1G Windows recovery environment /dev/sda6  1951281152 1953523711    2242560   1.1G Windows recovery environment /dev/sda7  1843265536 1851078655    7813120   3.7G Linux swap /dev/sda8  1851078656 1890140159   39061504  18.6G Linux filesystem /dev/sda9  1890140160 1927151615   37011456  17.7G Linux filesystem  Partition table entries are not in disk order.   Output of sudo parted -l:  Model: ATA TOSHIBA MQ01ABD1 (scsi) Disk /dev/sda: 1000GB Sector size (logical/physical): 512B/4096B Partition Table: gpt Disk Flags:   Number  Start   End     Size    File system     Name                          Flags  1      1049kB  525MB   524MB   fat32           EFI system partition          boot, esp  2      525MB   660MB   134MB                   Microsoft reserved partition  msftres  3      660MB   944GB   943GB   ntfs            Basic data partition          msftdata  7      944GB   948GB   4000MB  linux-swap(v1)  8      948GB   968GB   20.0GB  ext4  9      968GB   987GB   18.9GB  ext4  4      987GB   987GB   472MB   ntfs                                          hidden, diag  5      987GB   999GB   11.9GB  ntfs                                          hidden, diag  6      999GB   1000GB  1148MB  ntfs                                          hidden, diag   Model: SRT USB (scsi) Disk /dev/sdb: 32.5GB Sector size (logical/physical): 512B/512B Partition Table: msdos Disk Flags:   Number  Start   End     Size    Type     File system  Flags 1      1049kB  32.5GB  32.5GB  primary  fat32        boot, lba   Please guide me how to resolve this problem.


I am trying to disable all options in all select boxes with specific value on page.  If there are 5 select boxes and each have 4 options. Like this:  <select>     <option value="1">1</option>     <option value="2">2</option>     <option value="3">3</option>     <option value="4">4</option> </select>  <select>     <option value="1">1</option>     <option value="2">2</option>     <option value="3">3</option>     <option value="4">4</option> </select>  <select>     <option value="1">1</option>     <option value="2">2</option>     <option value="3">3</option>     <option value="4">4</option> </select>   I want to disable all options with value 3 on whole page, how would i achieve this?  $("select option["+previous+"]").attr('disabled', 'disabled');   But this is disabling Select option with selected value 3.  Any help will be appreciated.

If you know the Index, Value or Text. also if you don't have an ID for a direct reference.  ,  and  are all helpful answers.  Example markup  <div class="selDiv">   <select class="opts">     <option selected value="DEFAULT">Default</option>     <option value="SEL1">Selection 1</option>     <option value="SEL2">Selection 2</option>   </select> </div>


In "Eastwatch" (Game of Thrones, S07E05), in the scene with Gilly and Sam, Gilly is reading from the records of High Septon Maynard. From this scene, we can infer that this High Septon performed an annulment for Rhaegar Targaryen and married him in secret. I think that it is safe to assume that it was to Lyanna Stark.   From earlier episodes, we know that this was the coupling that produced Jon Snow. Now, given that they were married and that Rhaegar was the eldest of the siblings, does this make Jon the actual heir over Daenerys?

This might be a duplicate or debatable. But as far as the releases of the books & TV series, who should rule Westeros as per the laws of that continent? Ignore the usurpers.  Is it Daenerys Targaryen or Jon Snow (Targaryen)?  If there are Targaryens alive, how can Baratheons be rightful rulers? If I'm not wrong the Baratheons are usurpers, right?


How do you get the Pokeflute in Pokemon Fire Red and Leaf Green

I'm trying to get past a Snorlax and I need a Poké Flute to wake him up—how do I get one?


As per Einstein's Theory of General Relativity, I understand that 'the Earth's ground is accelerating towards us at 9.8m/s^2. This is why we're falling towards the center of the Earth, as GR doesn't accept gravity as a force'. So, if a car is supposed to accelerate constantly, at one point of time, it would reach its top speed. Won't the same happen with Earth, as the top speed will be the speed of light? Thank you.

I know this question has been asked in other forms, generally regarding the balance of forces.  This time I want to focus on motion.  I've got a laser accelerometer on my desk.  It tells me that I'm accelerating at $9.8~\rm m/s^2$.  For the first experiment I'm travelling in space.  I pick a nearby star and discover that I move about $490$ meters in $10$ seconds from that star.  For the next experiment I'm on the surface of Earth.  I measure the same acceleration with my laser accelerometer.  I pick a spot (the center of the Earth) and discover I don't move at all in $10$ seconds.  How is acceleration without motion possible?


The viewport render is correct but the actual rendered image is a black screen. This happened to me before and i even posted a question regarding that and the problem was a hidden object. But this time I made sure there was no hidden object in my project but it still doesn't work. I tried the to unhide all the objects and nothing came out which could disrupt the camera view. Your help is much appreciated. Thank you

A scene I made is not rendering, at all. This grey screen stays the same and nothing changes.  Here are my settings:  [


How to pass a OUT String parameter to a function ? something like   public static Address getFromLocation (OUT string ErrorMsg) { ... }   If some errors are found in the getFromLocation then the function will update the ErrorMsg that i can use later.  If it's not possible, how in my example, can i retrieve the errorMsg ?

I always thought Java uses pass-by-reference. However, I've seen a couple of blog posts (for example, ) that claim that it isn't (the blog post says that Java uses pass-by-value). I don't think I understand the distinction they're making. What is the explanation?


Pls discuss just the method below, and refrain from other methods. The  below looks wrong to me, because both the exponent and base are $x$! So how can you possibly pretend or playact that they're not, and treat the exponent and base separately as constants?     I once asked students to find the derivative of $x^x$ (with respect to $x$). One student figured that if the exponent were a constant then the answer would be $xx^{x-1}$ which is to say $x^x$, while if the base were constant the answer would be $x^x\log x$, so she added the two together to get $x^x+x^x\log x$. I was just about to mark the answer as wrong, when I realized that she had arrived at the correct answer – and, later, realized that it wasn't a coincidence, her unorthodox method actually works in a more general setting.

As many of you probably know, when you take the derivative of $x^x$, you cannot treat it as either a exponential function ($a^x$) or like a function of the form $x^a$.   If you treat it like $x^a$ then you get an aswer of $xx^{x-1}$, which is just $x^x$.  Treat it like $a^x$, and you get $x^xln(x)$.  The correct derivative is $x^x(ln(x)+1)$, which you get by doing implicit differentiation after taking the natural log of both side.  This is the same as $x^xln(x)+x^x$, which happens to be the combination of the "wrong" derivatives you get when treating $x^x$ as the 2 different types of functions I specified earlier.  Is there any real logic behind this or is it coincidence. Also, could this also be applied to other function hybrids like $x^x$?


I have added a custom post type called: "Partners", what I want is that when a new one is created, a notification appears in the sidebar of Wordpress.  For example:    regards!

I created my own contact form and I'm using WP_List_Table to display submitted forms in wp-admin. I edited  example WP_List_Table from github and it works fine.   This is how I add my custom admin menu page:  function contact_form_create() {     add_menu_page('Contact Forms', 'Contact Forms', 'administrator', 'contact-form', 'contact_form_page_handler'); }  add_action('admin_menu', 'contact_form_create');   But now I want to make a notification. So when visitor submit a contact form, then my table shows me a notification in wp-admin like this:


When a user tries to post a new question on Stack Overflow for the first time, he's redirected to .  For a new user who is usually not very patient, it's just a wall of text. He goes over the words quickly, ticks the obvious "thanks, I will keep these tips in mind when asking " checkbox and then he might easily miss the "proceed" link which is both aligned to the right, far far away from the checkbox and has a light gray color.  In such a case the user will scan the page again looking how to get past that obstacle, then to the right of the big search box he'll see this:        Now he thinks "great, let's discuss my question on meta (whatever meta is)" and click the link happily and full with hope. He gets to a site with a very similar design to Stack Overflow. Remember that he's under the impression that's the place to discuss his question.  The "Ask Question" button is 100% the same as the one on Stack Overflow, so our dear user clicks it. Jackpot! There's no irritating wall of text asking him to confirm things he'll never really remember.  He posts the question there and quickly forgets the bumpy way he went through... until his question is downvoted and deleted on that mysterious "meta" site he never really meant to reach in the first place.  What can we do? I'm open for suggestions or objections, if you don't think that's the source for many of the programming questions we see here on daily basis.

As you may know, the amount of questions here that actually belong on Stack Overflow is huge. If I'm allowed a guess, it probably happens a few times a day.  Why are people posting in the wrong place?  Now, what are the reasons for this? What do these users think? (Do you have a guess why this is?)     "Hey, Stack Overflow is cool, but there's a meta link, now that looks even more awesome, let's click it and ask there!"   What are – from your experience – the reasons for new users posting here?  And then there's this comment exchange that makes me wonder:      What could be done to prevent it?  Now, obviously those people have skipped a few reminders:   This one here:  That one:  And this one:    My question is: Is there anything that we can do to prevent people from asking in the wrong place? I know these people need a bit more than a gentle reminder and a passive note somewhere in a sidebar.  What about Jeff's question about a . Would it be an option to apply this algorithm to meta questions?  if (post contains code) and (user is new)   show alert ("Your question probably belongs on Stack Overflow,    our Q&A for professional and enthusiast programmers")   What do you think?


I was trying to execute a query on data.stackexchange.com, since I wasn't logged in I get  asked to solve the captcha (Which is fine).  However data.stackexchange.com  is failing to display the captcha for me and presents this error:

When I tried to run , I got the below screen:    The captcha is missing!  I tried in other browsers too.    Update:  From @Oded's comments, I changed to HTTP and it was working perfectly.  Out of curiosity I would like to know why the captcha isn't working when accessing Data Explorer over HTTPS.


I am new to c++ I have 2 queries regarding how a base constructor is called.  1.) Lets say my code looks somewhat like this.  #include<iostream> using namespace std;  class Base  { public:     Base()    { cout<<"Constructor: Base"<<endl; }     virtual ~Base()   { cout<<"Destructor : Base"<<endl; } };  class Derived: public Base { public:     Derived()   { cout<<"Constructor: Derived"<<endl; }     ~Derived()  { cout<<"Destructor : Derived"<<endl; } };  int main()  {     Base *Var = new Derived();     delete Var;     return 0; }   I was told that a base constructor has to be called explicitly before defining the derived constructor by initialization list. But here without any call to the base constructor, the code is working as expected.  **The output for the above problem is**  Constructor: Base Constructor: Derived Destructor : Derived Destructor : Base   2.) Now suppose the base class constructor takes parametrized arguments, but the derived constructor is empty. In the main function, I declare a derived object without any argument to the constructor. what will happen? Any way to separately pass the base constructor of that object an argument?  Thanks.

What are the C++ rules for calling the base class constructor from a derived class? For example, I know in Java, you must do it as the first line of the subclass constructor (and if you don't, an implicit call to a no-arg super constructor is assumed - giving you a compile error if that's missing).


how to change partition ntfs to ext4 with out formatting ? my linux all  partition automatically moving ext4 to Ntfs.how i change it?

I have a hard drive from an Ubuntu system that contains only media files. I would like to move that drive to a Windows 10 computer without losing all of the media. Is this possible, and if so, how can it be done?  I don't want to just mount the ext4 drive in Windows. I want to convert the drive from ext4 to NTFS.


I will first say, it has been a couple years since I have written Greasemonkey/Userscripts last and I am a bit rusty with my JavaScript, and this should be a simple question.  I am trying to detect if a specific textbox has focus. (I plan on running a script when a specific box has focus and the user presses the enter key.)  My issue is that the site does not have an ID tag for the textbox, only a name tag <input type="text" size="20" value="" name="Category_Product_Search"></input> and nearly all of the tutorials that I see requires the textbox to have an ID tag.  Thank you,  Charles

I would like to find out, in JavaScript, which element currently has focus. I've been looking through the DOM and haven't found what I need, yet. Is there a way to do this, and how?  The reason I was looking for this:  I'm trying to make keys like the arrows and enter navigate through a table of input elements. Tab works now, but enter, and arrows do not by default it seems. I've got the key handling part set up but now I need to figure out how to move the focus over in the event handling functions.


My full name on passport is Amir Hisham Ahmed Al-Attraqchi (first three names + surname). In my publication, I only used the first and the surname (i.e. Amir Al-Attraqchi). Is it going to be a problem proving the publications to be mine?  I'm worried about proving this when applying for new universities, promotions or fellowships

In some of the questions regarding author name, it is mentioned that people can use whatever they like, however, they must be consistent across their publications.  When it comes to being hired by a university for a tenure track position or by another principal investigator as a researcher, how can someone prove that they are the author of papers when their author name does not exactly match the one on their ID card? How can a principal investigator be sure that the publication list does actually belong to the person claiming them?


I have the sets of string that will always start with ?20 and end with ?30 or ?31 or ?32 and so on.   For example  ?20needed_text?30 ?20needed_text?31 and so on...   I need to extract the needed text. It is necessary to stress that needed_text may contain any character including digits, letters, specific characters and etc.   Can anyone help with a proper regex?   I tried the following pattern but it does not work:  "\?20(.*?)\?3[0-9]"   this is my code. I get empty values in my echo...  set regex = new regexp   regex.global = true regex.pattern = "\?20(.*?)\?3[0-9]" set payment_purposes = regex.execute(row) for each payment_purpose in payment_purposes  wscript.echo payment_purpose next   Thank you.

For example, this regex  (.*)<FooBar>   will match:  abcde<FooBar>   But how do I get it to match across multiple lines?  abcde fghij<FooBar>


What causes a moving positive point charge moving right in a uniform into the page magnetic field to specifically move upwards? why not downwards?  Upwards and downwards (on the plane of the paper) are viable options. why does the charge  only move upwards?  Doesn't this violate the natural laws of symmetry?  Are we just supposed to accept this? Why is the right hand rule more special than the left hand rule?  The direction of the magnetic field can be given by a unit north pole easily (uniformly into the page). So isn't the direction of the magnetic field already fixed?  The reason I ask this is because many posts imply that electromagnetism is parity invariant as we use the right hand rule twice in many cases, negating its arbitrariness, but here we use it only once.

At school I learnt the  to remember the resulting direction of different phenomena, such as geometrical cross products, mechanical torque, or the direction a screw will move when turning it. This directions are however decided by humans, and we could have easily defined the directions in the opposite way.  However the right hand rule also predicts phenomena which is not arbitrarily set by humans, but is intrinsic to the nature. If you have a coil in which you put some current, and the nature creates a magnetic field in a direction perpendicular to it, the direction depends on the right hand rule.  My question is, why this direction and not the opposite? Nature tends to be symmetric and not have apparent preferences for two equal options, so in a so why is one direction preferred over the other one? Why doesn't a "left hand" rule apply?


I wrote a pretty detailed tag wiki (over 800 words) for Kotlin but it seems like the original author of this tag wiki is not active anymore as he was last seen in April.  Is there any way my edit can still be approved for example by an administrator or something like that?

When clicking "edit" I see:  Your edit will be placed in a queue until it is peer reviewed. We welcome edits that make the post easier to understand and more valuable for readers. Because community members review edits, please try to make the post substantially better than how you found it, for example, by fixing grammar or adding additional resources and hyperlinks.  Like:     Likewise, when I am not logged in, clicking "improve this question" or "improve this answer" shows:  You are not . Your edit will be placed in a queue until it is .  And when I click 'Save', I get:  Thanks for submitting an edit. It is only visible to you until it's been approved by trusted community members  Like:     Who can suggest an edit? Where do suggested edits go? Who can vote on a suggested edit? How do suggested edits get reviewed? Can I earn reputation? What about abuse or bad edits? Sometimes the Community user approves or rejects my edit. Why is that? When can I not suggest an edit? Is there a minimum change requirement for a suggested edit? How do I check my suggested edit history? I disagree with the reasons why my suggested edit was rejected. What can I do? How do I know whether there are edits waiting for review? Someone suggested an edit to my own post, and the reviewers took the wrong action. What can I do? Are tag wikis included in this scheme? What do the "Improve Edit" and "Reject and Edit" buttons do? Why are apparently valid links to rejected edits resulting in 404 errors?   For more information about editing, see "" in the .


I want to validate url strings and add  if needed.  The url may be "google.com" or "google.co.in" so it is hard to relay on the end of the string.  How can i do it?

I have an input String say Please go to http://stackoverflow.com. The url part of the String is detected and an anchor  is automatically added by many browser/IDE/applications. So it becomes Please go to http://stackoverflow.com.  I need to do the same using Java.


I am using Ubuntu 18.04 LTS. In this system, while I want to take a screenshot of my entire screen of laptop, press prt sc key, then the photo is automatically saved in Picture folder. No option appears asking for File Name and for where to Save.   But these options are available in Ubuntu 16.04 LTS. My question is that can I get the option that will ask for a File name and where to save option each time?

I take screenshots a lot. I usually take screenshot of an area, I then recheck if I have the desired area and then copy it to clipboard.  I want to change this behaviour so that immediately upon  pressing Shift+PrntScr the screen capture application allows me to select an area, and immediately afterwards it provides me with the option to save to a particular location or clipboard.  I want Shift+PrntScr to bring up a pop-up screen like this:


My PC have 8gb ram. recent I install ubuntu 32 bit and I saw the system show 8gb. should I install ubuntu 64 bit or 32 bit?

What is the difference between 32-bit and 64-bit Ubuntu? I've heard the 64-bit platform performs better and can detect more than 4GB of RAM. Also, while some apps haven't ported to 64-bit yet, ia32-libs lets a 64-bit machine run them.  If so, why not promote 64-bit over 32-bit?


I saw a math symbol looks like this, anyone know what does it stands for? $$-V^t + G[D^T]^+$$

I was skimming through Vardi & Zhang's paper on "A modified Weiszfeld algorithm for the Fermat-Weber location problem".   It is available at   If you open the paper and scroll down to page 3, you'll find equation 12, which I found to be odd. There is a lone plus sign in the exponent/superscript. Does anyone know what that means? Could it be that this simply a typo and that the "+" sign refers to an addition operation instead?  Many thanks for your help! Nicolas


Whenever I see a visualization of support vector machines, the separating hyperplane always has three support vectors. I don't understand why it isn't two. Given that the best separating hyperplane only has to maximize the size of its margins from the nearest points of each class, I would think that only two support vectors, one from class A, and one from class B, would be required. Can anyone explain to me why this is not the case?

I wanted to check if I am understanding the concept of the support vectors correctly. Let's say I am not using any kind of kernel, and it is a hard-margin SVM.  In this case, whatever the number of the dimensions is for our features, the minimum possible number of support vectors equals to 2 (1 for +, 1 for -). Am I correct? Do we still need more support vectors even in such an ideal case in $R^{d}$?


Bascom uses a special format to comment out blocks of code. I want a RegEx that matches this block to be used in SyntaxHighlighter.  These comment blocks starts with '( and ends with '). Yep, it's so stupid.  Example input:      bla     '(     test     test     ')     blubb   I tried:     '\(.*?\)' and many others without success.  Expected return after replace:      bla     #####     blubb   where ##### is the replacement.  Basically just like C++ & similar /* .. */ rule. But I can't get it working.  Thanks in advance!


I need to trace and monitor client login connections (successful and failure) to our important SQL servers (20 MSSQL Server). What method do you recommend?  Note: I think enabling "both failed and successful logins" to windows event logs may create large log files so in my mind it is last option. Also i think auditing may affect database performance so this is last option too.

Good morning, please, has anyone used logins audit without using the Profile?  My client needs an audit that displays the logins that connected to the bank and after they disconnected.  In the case the profiler believe it is too heavy to keep active all the time collecting.  Do you have anything that might help us in this case?  thank you Carol Lavecchia


Amit: I will send you an email. Me: OK.  After one day how can i tell this indirectly. Should i say Amit told me that he would send me an email or Amit told me that he will send me an email.  It is now past because he didn't send me an email It is also possible he can still send me an email  I am confused should i use will or would?

I know the past tense carries the past tense in every dependent clause, but referring specifically to places or to things that are eternal, like the Earth, seems a bit weird and therefore we sometimes (I believe incorrectly) say     He didn't know that New Jersey was actually on the East Coast.   Because it still is. Or     He thought the Earth was round.   So is it square now?  Logically speaking, would you consider the use of past tense here a bit confusing in a day-to-day speech in these examples? Would you instinctively opt for using the present tense?


Today I notice that even if all the statistics works well and updates correctly for me and other, user stats in the top bar were all down to 'zero'.  A picture will describe better the problem than words :    This is not correct, as you can see in my . Do you guys experiment the same or is it because stats have been initialized at the beginning of the month (and week). I've never noticed this before, however, maybe I've looked bad...

The daily, weekly and month reputation on not appearing on either the StackOverflow or the Meta flyout that appears when hovering over the username.    Across the board everything is zero. I am seeing this in both Firefox and Chrome.


I wrote a small piece of code that rounds a number to the closest multiple of 0.005 but it produces a weird output, that I didn't expect. I am using Python version 3.7.3  Here is the code:  number = 1.639 print(5 * round(number / 5, 3))   Output  1.6400000000000001   Expected output  1.64   Check this  for detailed output on different values.  Can anyone tell me why this happens?

Consider the following code:   0.1 + 0.2 == 0.3  ->  false   0.1 + 0.2         ->  0.30000000000000004   Why do these inaccuracies happen?


Anyone know the answer to this? I have reached level 54, and wonder how much longer I can go..

In Oblivion, the way the game worked, the max level possible was based solely on your choices for primary skills, and could vary anywhere from between 45 and 53 (with soft-caps at 29 and 35 in terms of NPC leveling) or when you maxed all of your character attributes at 100.  What's the level cap in Skyrim? Is it a hard or soft cap -- once you hit it, can you continue to 'level' your skills and unlock perks anyway?


This schematic has a LM107 op-amp at its heart. It seems that it is now discontinued. Will a uA741 op-amp be a good substitute? If not, why not? What would be a good substitute?  Thanks.

Simple enough question. Why not use a  in a target circuit or anyone's target circuit? What are the reasons not to use it? What might be the reasons to still choose this part?


I am compiling a pdf in Overleaf but even if there is a minor change, the pdf will be compiled from scratch and that will take a while for a large document. How to avoid this? Is there an option to specify a setting so that only a part that was modified will be changed in the pdf?

I see that there a number of questions (, , , , ) on best practices, none of them answer the issue I am going to talk about.  We all need to prepare large documents (or slides) from time-to-time. And once you have reached a certain number of pages, you find that compiling the whole document takes a substantial time, which you need to do to check that the part you have written is error free, specially if it contains a number of images.   To circumvent the situation, I have used the following practices over years to keep compile time at minimum.   Divide the document in to many chapters: The chapters are put in separate files. Only the one I am working one is uncommented.  \documentclass{book}  \begin{document}  %\input {chapterone.tex} \input {chaptertwo.tex} %\input {chapterthree.tex} %\input {chapterfour.tex}  \end{document}    The above technique can also be used for \include.   Keep a preamble replica of the main file in a temporary file (build file): I use this technique when I am preparing a presentation with many slides, say a hundred. Prepare a main file, copy it to another build file. Delete everything between  \begin{document} and \end{document} in the build file. Prepare a slide (or a group of slides) in the build file. Cut and paste the contents between \begin{document} and \end{document} in the build file to relevant location in the main file only when satisfied with the output (image locations, overfull boxes etc.)     We can hear your inputs about the best practices you practice when a you are preparing a document or presentation from scratch.    Now, I have failed to find a good answer in the case when you have finished the whole document or presentation and now you need tweaking the small things, may be edit a text here, add an image there. What will be your best practice?  Perhaps, again keeping only one chapter uncommented will be usable here. But what about large presentations? May be adding a \end{document} just after the point-of-change will be beneficial, but only if you can put that before midpoint of the file.  Commenting a part of the file will also work, but that is error-prone, at least for me.


I got an NUC i5 core assembled. Want to install Ubuntu 12.04 LTS (need that specific version for ROS HYDRO robot). Now looking at what Ubuntu image to pick. Selected the PC (Intel x86) desktop.iso image. But see that it is a 32 bit OS type when starting from USB. The other image I can select is 64-bit PC (AMD64) desktop CD giving me an AMD64.iso. Is that only for AMD 64-bit processor? Where is the 64 bit x86 image?  This is the text from the releases.ubuntu.com/precise website:  There are two images available, each for a different type of computer:  PC (Intel x86) desktop CD For almost all PCs. This includes most machines with Intel/AMD/etc type processors and almost all computers that run Microsoft Windows, as well as newer Apple Macintosh systems based on Intel processors. Choose this if you are at all unsure. 64-bit PC (AMD64) desktop CD Choose this to take full advantage of computers based on the AMD64 or EM64T architecture (e.g., Athlon64, Opteron, EM64T Xeon, Core 2). If you have a non-64-bit processor made by AMD, or if you need full support for 32-bit code, use the Intel x86 images instead.  Note also when I select 64-bit Ubuntu 14.04.1 LTS from the main ubuntu page to download (on an intell machine) it collects the desktop-amd64.iso file to download?  Where do I get the 64-bit ubuntu 12.04.5 iso file for I5 NUC?

What is the difference between standard i386 download and the amd64 download of Ubuntu 11.04? I am currently running the i386 on an amd machine, would my system work better with the amd64 download instead? (my machine was running Windows 7 64bit, but I neglected to look at that prior to installing Ubuntu).


I have a base class such as :   public abstract class BaseClass {  }   and I also have sub classes :   public class SubClassA extends BaseClass{} public class SubClassB extends BaseClass{} public class SubClassC extends BaseClass{}   I want to get all sub classes by Base class like below:  List<Class> getSubClassesByBaseClass(BaseClass.class);   How can I do that ?

How does one go about and try to find all subclasses of a given class (or all implementors of a given interface) in Java? As of now, I have a method to do this, but I find it quite inefficient (to say the least). The method is:    Get a list of all class names that exist on the class path Load each class and test to see if it is a subclass or implementor of the desired class or interface   In Eclipse, there is a nice feature called the Type Hierarchy that manages to show this quite efficiently. How does one go about and do it programmatically?


How to pass data from RecyclerView of fragment  to another fragment.i getting error. when I start the app, the app crash within 5 seconds with the message My RecyclerView of fragment..   @Override public void onBindViewHolder(final MyViewHolder holder, final int position) {     final Categories categories = categoriesList.get(position);     holder.name.setText((categories.getName()));     Glide.with(context).load(categories.getThumbnail()).into(holder.thumbnail);     holder.name.setOnClickListener(new View.OnClickListener() {         @Override         public void onClick(View view) {            String catId= String.valueOf(categories.getId());             Toast.makeText(context,catId,Toast.LENGTH_SHORT).show();             AppCompatActivity activity = (AppCompatActivity) view.getContext();             AudioFragment myFragment = new AudioFragment();             Bundle bundle=new Bundle();             bundle.putString("name", catId); //key and value             myFragment.setArguments(bundle);             activity.getSupportFragmentManager().beginTransaction().replace(R.id.frag_container, myFragment).addToBackStack(null).commit();          }     }); }   New Fragment  public class AudioFragment extends Fragment {  @Override public View onCreateView(LayoutInflater inflater, ViewGroup container,                          Bundle savedInstanceState) {     // Inflate the layout for this fragment     String CAT_ID = getArguments().getString("name");     Toast.makeText(getContext(),CAT_ID,Toast.LENGTH_SHORT).show();      return inflater.inflate(R.layout.fragment_audio, container, false); }   }

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?


This is my pom.xml   <build>     <plugins>         <plugin>             <groupId>org.apache.maven.plugins</groupId>             <artifactId>maven-jar-plugin</artifactId>             <executions>                 <execution>                     <goals>                         <goal>test-jar</goal>                     </goals>                 </execution>             </executions>             <configuration>                 <archive>                     <manifest>                         <addClasspath>true</addClasspath>                         <mainClass>com.ttn.dailyreport.RunTest</mainClass>                     </manifest>                 </archive>             </configuration>         </plugin>     </plugins>   And this is the manifest.mf -   Manifest-Version: 1.0 Archiver-Version: Plexus Archiver Built-By: Shubham Class-Path: poi-3.17.jar commons-codec-1.10.jar commons-collections4-4  .1.jar opencsv-4.0.jar commons-lang3-3.6.jar commons-text-1.1.jar com  mons-beanutils-1.9.3.jar commons-logging-1.2.jar commons-collections-  3.2.2.jar postgresql-42.2.2.jar log4j-1.2.17.jar mail-1.4.7.jar activ  ation-1.1.1.jar Created-By: Apache Maven 3.5.2 Build-Jdk: 1.8.0_161 Main-Class: com.ttn.dailyreport.RunTest  It has all the external jars in classpath still throwing class not found exception. Let me know if you need more details or code.

I want to package my project in a single executable JAR for distribution.  How can I make a Maven project package all dependency JARs into my output JAR?


I faced rather odd behavior when multiplying doubles.  Make a simple console application and try following code.  private static void Main(string[] args) {     var b1 = 3.1 * 100D;     var a1 = 4.1 * 100D;      // put breakpoint here and observe b1 and a1 values, to me they are       // b1=310, a1=409.99999999999994     Console.WriteLine(a1);     // notice that Console.WriteLine actually returns 410 }   I suspect this is something with the double representation in binary but I can't explain myself how it is possible, can you help me out?  Also if you cast a1 to decimal it becomes 410 somehow...  I tried compiling against C# 3.0 and C#7.0 both gave the same results. I am reproducing this in Visual Studio 2017.


Since I study 3 years i ask myself very often where does this equation come from? $$e^{i\theta} = \cos(\theta)+i \sin(\theta)$$ Is it found by series expansion?

Could you provide a proof of Euler's formula: $e^{i\varphi}=\cos(\varphi) +i\sin(\varphi)$?


import java.io.BufferedReader; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.IOException; import java.io.InputStreamReader; import java.io.PrintWriter; import java.io.Reader; import java.util.Arrays; import java.util.LinkedList;  public class ProjectTwoAccessControl{    // public static void fOrAAdd(String x,PrintWriter n){ //      n.write(x); //  }   public static void main(String [] args) throws IOException{     PrintWriter friends = new PrintWriter("friends.txt");      PrintWriter audit = new PrintWriter("auditlog.txt");    try { FileInputStream inputCommands;      inputCommands = new FileInputStream("test.txt");     BufferedReader br = new BufferedReader(new InputStreamReader(inputCommands));     String line;     while ((line = br.readLine()) != null){ //2         String[] command = line.split(" ");         System.out.println(Arrays.toString(command)); //      for(int i = 0; i < command.length;i++){ //1         if (command[0] == "friendadd"){             friends.write(command[1]);             audit.write("Friend " + command[1] + " was added.");          } //      } //1  } //2 }//try end catch (FileNotFoundException e) {     System.out.println("No file found by this name"); }     friends.close();     audit.close();  }          }   I am attempting to make a social media style of access control for a school assignment, and am going to continue working on this all evening, but I cannot figure out why the PrintWriters are not writing. I added in to print the array "command" out, and it seems to be working correctly, but nothing will print to my friends.txt or audit.txt.

I've been using the == operator in my program to compare all my strings so far. However, I ran into a bug, changed one of them into .equals() instead, and it fixed the bug.  Is == bad? When should it and should it not be used? What's the difference?


I created an array and gave tems 1 to 12 values. I did this to later loop through a part of code with each name. for some reason i get an error at my firs array fill line: "Object required". any ideas? And doe the rest of this code make sense too?                  Dim sArray() As String                 Dim row As Long                 Dim i As Long                 Dim arrTot() As Long                 Dim arrLate() As Long            'Error here                 Set sArray(1) = "AAA CANADA INC."                 Set sArray(2) = "AEROTEK ULC"                 Set sArray(3) = "AKKA GROUPE AMERIQUE DU NORD INC."                 Set sArray(4) = "ALTITUDE AEROSPACE INC."                 Set sArray(5) = "ASSYSTEM CANADA"                 Set sArray(6) = "BERLETEX AERO DESIGN"                 Set sArray(7) = "MSB DESIGN INC."                 Set sArray(8) = "NORAMTEC CONSULTANTS INC."                 Set sArray(9) = "SATYAM COMPUTER SERVICES LTD."                 Set sArray(10) = "T.E.S. CONTRACT SERVICES INC."                 Set sArray(11) = "TATA CONSULTANCY SERVICES CANADA IN"                 Set sArray(12) = "TDM TECHNICAL SERVICES"                  Set vendor = Range("P2:P" & lr)                 row = 1                 For Each cell In invoicedates                     For i = 1 To 12                         If tbl1(row, 16) = sArray(i) Then                             arrTot(i) = arrTot(i) + 1                             duedate = cell.Value + 60                             If Date > duedate Then                                 arrLate(i) = arrLate(i) + 1                             End If                         End If                     Next                     row = row + 1                 Next

Hopefully an easy question, but I'd quite like a technical answer to this!  What's the difference between:  i = 4   and  Set i = 4   in VBA? I know that the latter will throw an error, but I don't fully understand why.


$$\int_0^{\infty} {e^{-ax}\cos{(bx)}} dx$$   I know I need to use integration by part method. But I'm not sure how does the improper integral take place?

I want to evaluate the following integral via complex analysis $$\int\limits_{x=0}^{x=\infty}e^{-ax}\cos (bx)\operatorname d\!x \ \ ,\ \ a >0$$  Which function/ contour should I consider ?


I'm having a bit of trouble understanding what exactly is meant by a  of a quantum field and its relation to the vacuum energy attributed to such a field.   Is the point, that due to the Heisenberg uncertainty principle, one cannot precisely determine the value of the field at a given point and as such its standard deviation is non-zero. So by saying that a quantum field is fluctuating is simply a handwavy statement of the fact that its value (in vacuo) at a given point in space-time is not prescisely determined (i.e. it is not well-defined) and this results in a non-zero vacuum energy?!   Or are quantum fluctuations simply the name that is given to higher-order corrections to correlation functions (for example $\langle 0\lvert T\lbrace\hat{\phi}(x)\hat{\phi}(y)\rbrace\rvert 0\rangle$) in perturbation theory, due to the fact that these corrections are represented by loops in the corresponding Feynman diagrams, which can heuristically be thought of as virtual particles being produced by fluctuations in the vacuum state of the quantum field?  Apologies if I'm spouting nonsense, I just want to understand this concept and thought it helpful to put down my current thoughts about it.

In popular physics articles and even some physics classes I've been to, the vacuum of space is described as being constantly full of quantum fluctuations.  Supposedly, all sorts of particle-antiparticle pairs at all scales are constantly appearing and disappearing.  We end up with a mental image of the vacuum as a roiling, choppy sea with all sorts of things going on, rather than a calm, placid background.  However, the vacuum, being the lowest-energy state of a theory, should be an energy eigenstate—which means it is time-invariant (except for a physically-irrelevant phase factor).  So it seems the vacuum really should not be seen as a dynamic entity with all kinds of stuff happening in it, as we're led to believe.   that     A “vacuum fluctuation” is when the ground state of a system is measured in a basis that does not include the ground state; it’s merely a special case of a quantum fluctuation.   So it sounds as if the existence of vacuum fluctuations is contingent on measuring the vacuum—in particular, measuring something that doesn't commute with energy (such as, I guess, the value of a field at a point).  How much truth is there to the idea that vacuum fluctuations are constantly happening everywhere, all the time?  Is that really a useful way to think about it, or just a myth that has been propagated by popularizations of physics?


Is there any shell extension which will enable Ubuntu 11.10 gnome-shell  users to view time at different locations ?

I looked everywhere but I couldn't find a way to display multiple clocks in GNOME 3. In classic GNOME and Unity, it is possible. Also, for some strange reason, additional timezones cannot be added to the clock using the time-date applet in classic GNOME. Any solutions?


parameters=$# # # #Error Conditions Error=1 Success=0 if [ $parameters = 0 ] || [ $parameters  -lt 2 ] then    exit $Error fi  # get the parameters pattern=$1 filepath=$2  day=`date +%d` month=`date +%m` year=`date +%Y` echo $day echo $month echo $year   enddate=$year$month$day  echo $enddate day1=01 month1=`date +%m` year1=`date +%Y` startdate=$year1$month1$day1 echo $startdate  cd $filepath # check for the file  # create the date variabe DATE_DIR=`date +%Y%m%d_%H%M%S`  while [[ $startdate -le $enddate ]] do   test=`find . -maxdepth 2 -name $1` if [ "$test" = "" ] then     echo 'files are found'           exit 0 else         echo 'files are not found'         exit 1 fi  done

How can I list recursively all files that were changed between 22.12.2011 and 24.12.2011?


Since the Chromium PPA is no longer maintained, for those of us preferring to use Chromium over Chrome, we have two options:   Build and Install from Source Download either 'beta' or daily builds (in a zip file)   Unfortunately for me, option 1 is overly complicated. I know how to compile most any other applications in Ubuntu but I've never been able to get chromium to build correctly.   I am currently using option 2. In Chromium I have the Chromium Updater installed (). This gives me quick access to the most recent 64bit versions.   Once downloaded, I install to /home/myuser/opt/chrome-linux. From this directory I can run the chrome binary. It works perfectly except for the fact that I cannot get it to act as my default browser.   I've tried, as root, installing the binary in /opt/chrome-linux/ with a symbolic link to the chrome binary in /usr/bin.  Unfortunately, this doesn't work as a non root user.   So my question is - How do I properly install a downloaded Chromium zip build so that it's listed as an option for the default browser?

Is there an easier way to install Chromium than what is described ?  Furthermore, is there an easier way to stay up to date with current Chromium releases rather than having to re-build Chromium each release? (a script which automatically grabs and installs the latest build possibly?).  Related:


We know maximise a window in OS X (like we do in Ubuntu Unity or MS Windows) is not currently possible.  Are there any third party extensions available from OS X App Store to achieve this?  (I don't want to install applications that are not in App store for security reasons.)

Unlike Windows, you cannot maximize a window in Mac with a click of the button. The little green (+) button next to the red and yellow buttons at the left of the windows does some strange stuff sometimes when you click it and doesn't do the expected operations.  How would you fully maximize a window on a Mac?


I want to make a table as an attribute  and retrieving it was successful but it comes with an error  public class Main {     public static class stock {         public int n;         public int t[];         public stock(int n)         {             t=new int[n];         }         public void display()         {             for(int i:t)             {                 System.out.print(i+"   ");             }         }     }     public static void main(String[] args) {        stock s=new stock(4);         stock c[] =new stock[4];         for(int j=0;j<2;j++)         {         for(int i=0;i<4;i++)         {             s.t[i]=i;         }         c[j]=s;         }         for(stock x:c)             x.display();     } }   this is the result with an error how can i get rid of it where is the problem

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 have a PNY 16GB USB drive that has worked great for a while. The other day, I tried saving something to the flash drive and I received a write protection error. Now I can't edit or save anything on the flash drive, though I can still open and read the files. None of the individual files have been marked as read-only. I read a bunch of stuff but couldn't figure anything out (I will refer to this website, though I found the same information in multiple guides and forum posts ).    I have examined the drive and haven't found any switches that I might have accidentally pressed. I tried using Regedit but the StorageDevicePolicies key didn't exist. I tried creating it and I set  WriteProtect to 0 but that did not work. I tried using DiskPart. I entered the required commands properly but afterwards when I viewed the attributes I still saw this:   .    Basically I have tried everything short of formating the drive. I have lots of files on the drive that I want to keep so if there is anything else I can do please let me know. Thanks!

When I plug in my USB flash drive, it shows up on my computer as write-protected or read-only. I am unable to transfer data to it, nor can I modify or delete any files already stored on it. I also cannot repartition or reformat the drive using Windows Disk Management, DiskPart, GParted, or other tools. The drive does not have a write-protect switch.  Why did this happen and what can I do about it? Is there a way to remove the write protection?  (Note that this can happen with some memory cards, too, as they often use controllers similar to those used in flash drives. In some cases, the system may report that the drive or card was formatted successfully even though it was never actually formatted; the original data reappears when the device is reinserted.)     This question comes up often and the answers are usually the same. This post is meant to provide a definitive, canonical answer for this problem. Feel free to edit the answer to add additional details.


If you try to log in from a meta site (meta.*.stackexchange.com), you get an "Untrusted Connection" from Firefox, even without HTTPS Everywhere enabled.  For example, I just tried this on meta.law.stackexchange.com and the certificate appears to be only valid for ssl8217.cloudflare.com, *.stackexchange.com, stackexchange.com domains, thus causing ssl_error_bad_cert_domain.  It has been over two years since this issue was reported, and it continues to appear.  Here's one version of the security warning, on Firefox:    It's 2016, and we should be having reliable HTTPS coverage by now, at least for login.

Steps to reproduce:   In Firefox (with ), visit a non-trilogy Stack Exchange site (for example, ) Get redirected to the HTTPS version Click on meta link (for example, )   What should happen:   Meta site opens   What happens instead:   "This Connection is Untrusted" message appears:      meta.movies.stackexchange.com uses an invalid security certificate. The certificate is only valid for the following names: *.stackexchange.com, stackexchange.com, meta.stackexchange.com, *.meta.stackexchange.com, *.stackoverflow.com, stackoverflow.com, serverfault.com, stackauth.com, sstatic.net, meta.serverfault.com, superuser.com, meta.superuser.com, stackapps.com, openid.stackauth.com (Error code: ssl_error_bad_cert_domain)   Notes:   It also happens if you visit  instead (you get redirected to HTTPS and the error occurs) Another random example,  Trilogy metas work,  works (but  doesn't - I am not sure what gave me that link) Replacing URL with https://*.meta.stackexchange doesn't work   Here is the screenshot:


I have become "friends" with someone on-line and he keeps asking me to go pick up a money wire transfer and purchase bitcoin with it, then send him a picture of the bitcoin receipt.  I've done it once for $200, now he's asking me to do it again and this time it's supposedly for $1,000. Now I'm getting suspicious.  Could this be a scam?

I have been "hired" by Nissan Motor as a key account specialist.  My first assignment is to cash two checks that I have received. Both were written by a customer who has already received the engines. The total is $2500. I am to cash the checks, get the money, take out my bonus and any other related expenses and deposit into a Bitcoin ATM. Then make copy of receipt and electronically send to my "manager".  I contacted a lawyer, was told to talk to the Department of Labor, who said they will not get involved, as this is between me and my employer. Any advice?


Let $(X,d)$ be a compact metric space and $f : X \to X$ be isometric, i.e. for every $x,y \in X$ : $ d(f(x),f(y)) = d(x,y) $. How I can show the following? $f(X) = X$  My first thought was to show the surjection $ x \in X \setminus f(x) $. Is this the right approach?   Thanks in advance

Let $f:\mathbb{R}^n\rightarrow \mathbb{R}^n$ be such that $\left\| f(x)-f(y)\right\| =\left\| x-y\right\|$.  Is $f$ necessarily surjective?  If this is so, you can prove (Mazur-Ulam Theorem) that $f$ is affine, and hence you could classify all isometries of $\mathbb{R}^n$.  However, at the moment, I can't think of any good ideas to prove that $f$ is surjective.  For that matter, is it even the case that $f$ must be surjective?  Any ideas would be most welcomed.  Thanks much!


An install of just Ubuntu 18.04 LTS fails.   I used "nomodeset", for I get no visuals otherwise.  Installation is smooth for most of the time, but when it restarts, it just loops on this black screen with a ton of white text and codes. At some point it loops with the same text, the screen blinks (as if it tries to move forward), but just loops the same text.  I suspect it may be stuck on the logo splash screen, since I didn't a black screen with text on my PC at all when installing there, just on my MacBook.  Erasing the disk before install fails.  Installing alongside another Ubuntu install fails.  Could it be the GPU driver?  Is my MacBook not supported by 18.04?   EDIT:  By console, do you mean grub? Yes i can press esc on bootup and get to grub. CTRL + alt + f3 does nothing for me, but i can get to tty1 when booting the live USB by setting boot parameters to "splash 3".  I get a GUI when booting to USB and installing, and it finishes the install just fine. It's when rebooting after i get stuck on a console spamming the same things, and i can't make out which lines are error codes and which are not, so i don't know what to post here.  I made the USB using rufus in Windows 10. xsession-error logs? How do i access that? with grub? Please remember i know very little about how linux works, so some sort of tutorial or explanation would be greatly appreciated :)  model is a Macbook Pro 13" mid 2010, aka. macbookpro 7,1. 2.4 GHz Intel Core 2 Duo processor (P8600) 6 GB 1066mhz RAM 128GB aftermarket SSD  After rebooting it alternates between these two.    EDIT 2 Now i got this   EDIT 3  So i managed to install 16.04. I'll stick with that until someone kindly suggests a solution to my problem, and i'll try to upgrade when they allow it late july :)  thanks for the help anyway!

I was running Ubuntu 17.10 on my mac (mid-2010) as a dual-boot with Refind as the boot manager. It was functional albeit non-optimal drivers for wifi and video card.  A day ago, the Software Updater app gave me the option to upgrade and I took it. It completed the install and clean up fully but I was unable to do a final restart due to power issues. Anyway, after the power issues were sorted out, I booted my laptop, only to find that it wouldn't boot into the OS and would get stuck in a loop at a screen which was filled with lines of code that made no sense to me.  So, I rebooted with option key and booted into recovery mode and ran check disk and fix broken packages and then resumed boot. Then it booted into the OS fine. I rebooted again, and then it went back to the screen with lots of lines of code which no sense. I tried the same thing again with the recovery mode again. And this time when it booted I picked the proprietary Nvidia drivers. Now when I boot, there is just a blank screen and I cant boot into recovery mode either because there is an error in EFI screen option.  So I boot into OS X and download the ISO file for 18.04 and make a bootable USB stick and boot into that from the EFI screen. Now, it boots and once past the orangeish blue bionic beaver wallpapers, it gets stuck in a loop at a message called setting locale.  So, at this point, I can neither boot into my HDD Ubuntu install nor into the Live Disk.  My next plan of action is to try and get an ISO of a previous version and try booting form that. I'd like to avoid that if possible and stick to 18.04.  EDIT 1: I flashed Ubuntu 17.10 onto the USB storage, and that boots fine. I'll try 18.04 once again. Also, I'm using Unetbootin for flashing the USB storage.  EDIT 2: This keeps cycling over and over when I live booted from a freshly downloaded copy of Ubuntu 18.04 ISO file flashed in to a USB:    Keep in mind that when I do this on the same USB with the ISO file for 17.10.1, live boots perfectly fine.   EDIT 3: I've given up. I'm doing a clean install of 17.10.


i have this long and ugly else if statement in python, is there a way to condense it into a shorter block of code maybe on one line or two if possible because it seems like there would be a way of shortening a piece of code like this  if p == "A": y = 10         elif p == "B": y = 11 elif p == "C": y = 12 elif p == "D": y = 13 elif p == "E": y = 14 elif p == "F": y = 15

I want to write a function in Python that returns different fixed values based on the value of an input index.    In other languages I would use a switch or case statement, but Python does not appear to have a switch statement.  What are the recommended Python solutions in this scenario?


From Strunk & White, Elements of Grammar, 3rd Ed., p.11: "When who introduces a subordinate clause, its case depends on its function in that clause."    They then give four examples without explaining which, if any, is incorrect.  They give no further comment on the four examples which are:   "Virgil Soames is the candidate whom we think will win."  "Virgil Soames is the candidate who we think will win." "Virgil Soames is the candidate whom we hope to elect." "Virgil Soames is the candidate who we hope to elect."    It seems to me that 2 and 3 are correct (since we think he will win, and we hope to elect him).   Is this what Strunk and White are driving at, or am I missing something more complicated?  Specifically I would like to reconcile number 2 with an explanation in A Grammar Book for You and I ... Ooops Me by C. Edward Good.   It says (p.138) to use whom for a clause that already has a subject.  It looks to me like number 2 above has a subject, we, and should therefore, according to Good, take whom as the relative pronoun.   Which is correct, Good or S&W?

I can never figure out whether I should use who and whom. Most people use who for both colloquially, but some people say this is not correct.  What’s the rule for using who and whom correctly?


If $x=(x_1.x_2,x_3,...,x_n,...)$ and $\sum^\infty_{k=1} |x_k|^p<\infty$,$p\geq 1$ can you help me to show that $\lim_{k\to\infty}|x_k|^p=0$?

Following the guidelines suggested in , I am going to post a proposed proof as an answer to the theorem below. I believe the proof works, but would appreciate any needed corrections.  Theorem If a series $\sum_{n=1}^{\infty}a_n$ of real numbers converges then $\lim_{n \to \infty}a_n = 0$


Does any standard "comes with batteries" method exist to clear the terminal screen from a Python script, or do I have to go curses (the libraries, not the words)?

Like most Python developers, I typically keep a console window open with the Python interpreter running to test commands, dir() stuff, help() stuff, etc.  Like any console, after a while the visible backlog of past commands and prints gets to be cluttered, and sometimes confusing when re-running the same command several times.  I'm wondering if, and how, to clear the Python interpreter console.  I've heard about doing a system call and either calling cls on Windows or clear on Linux, but I was hoping there was something I could command the interpreter itself to do.  Note: I'm running on Windows, so Ctrl+L doesn't work.


I managed to somehow completely delete the Smooth brush in Blender. I've tried closing and opening the project, uninstalling and re-installing the app...nothing! Thanks in advance :) PS: if you know how to delete that repeated brush, that would be awesome as well!

I am quite new in using Blender 2.78 so please understand if this is an absurd question. I was sculpting a model in Blender (using Crease tool) then after I've exited and re-opened the project, Crease tool and Brush tool are missing! How can I restore them?   I have created a new blender file then opened the old file > append > brush but I still don't see the brushes I need.


If you leave a ball weighing 10 kg at a height of 500 km above sea level (neglecting air friction).  How can calculate how long the ball hits the ground and what will be its speed?   I know that: On earth I can calculate the time taken to the object to fall by this equivalent:  x = x0 + v0t + (at^2)/2 x = 0 x0 = 500000 v0 = 0 a = -g = 10 m/s^2 0 = 500000 - 5t^2 t = 316.227sec   Also I know how to calculate the force between objects:  g = GMm/r^2

The Problem For a small mass a distance $R_i$ away from the center of the Earth, how long would it take for the object to fall to the surface of the Earth, assuming that the only force acting upon the object is the Earth's gravitational force?  Relevant Information The following discussion seems to have solved exactly the same problem:   However, upon working out the mathematics, I'm not exactly sure how to evaluate the constant of integration.   A Partial Solution $$ F=\frac {-GMm}{s^2} $$ $$ a=\frac {-GM}{s^2} $$ $$ \frac {dv}{dt} = \frac {-GM}{s^2} $$ Multiplying by $v$ and then integrating by $dt$ on both sides, we have $$\frac {1}{2} v^2=\frac {GM}{s} +c_1$$ where $c_1$ is a constant of integration. Substituting initial conditions of $v=0, s=R$, we have $$\frac {1}{2} v^2=GM(\frac {1}{s}-\frac{1}{R})$$  At this point of time, when I use Wolfram Alpha, I get  $$c_2+\sqrt{\frac{2}{R}}t=\frac{\sqrt{s}(s-R)+R\sqrt{R-s}\times{\tan^{-1}(\sqrt{\frac{s}{R-s}})}}{\sqrt{GM(R-s)}}$$  where $c_2$ is a constant of integration. Substituting initial conditions of s=R, t=0, we find that the term $$\tan^{-1}(\sqrt{\frac{s}{R-s}})$$ is undefined. At this point, I'm stuck. Any ideas on where I've made the mistake here?  (For those interested, this question was inspired by the Greek myth which states that a bronze hammer dropped from heaven would take 9 days to hit the Earth and would reach on the tenth).


We are totally panicking about our 5 hour layover at Ataturk on the 19th July. We will be flying Turkish airlines and need to stay at the airport for 5 hours till we board our onward flight to Billund, Denmark No other airline tickets are available.  Is it safe? Would the airport be affected?  Honest opinions pls!

Reuters  in Turkey. What are the consequences of this for people who travel to Turkey? What about passengers transiting through Turkish airports?


This is the LaTex code:   \begin{figure}   \centering    \includegraphics[width=80mm]{PLA.pdf}   \caption{Some figure} \end{figure}   When I change the width to 80 it causes the problem but when I change the width to something like 55, there will be no problem.  The spaces are depicted in the picture:

I'm writing my bachelor-thesis and have a couple of small sub-sub-sections explaining conversions, like in the following  \subsubsection*{Assignment}  This document only explains non-compound assignments. The other kind, i.e \texttt{a += b}, is supported by the language too, but is not yet implemented.   \begin{itemize} \item If the first is an \texttt{auto} variable, no conversion takes place when assigning       the right hand side to the variable designated by the left hand side.  \item Otherwise, an assignment conversion takes place converting the given value to the type       of the designated variable.  \item Assignment requires an lvalue as the left hand side, and yields an lvalue result.  \end{itemize}  \subsubsection*{Multiplication} % ...   But latex renders it quite ugly with much space in between the items. I think it does so to fit the whole page. How can I tell it not to do so? Is what I'm doing right at all?


I am trying to make a function which checks if the number given is in a specific array. But when I enter a number which is in the array it still alerts bestaat niet but it should alert bestaat Does someone know why it alerts the wrong message? Here is my array: var baas = [     2951,     2952,     2953,     2954,     2957,     2961,     2969,     2981,     2984,     2985,     2986,     2988,     2989,     3341,     3342,     3343,     3344,     3351,     3352,     3353,     3354,     3355,     3356,     3361,     3362,     3363,     3364,     3366,     3371,     3372,     3373,     4201,     4202,     4203,     4204,     4205,     4209,     4251,     4254,     4255,     4271,     4273,     4284,     4285,     4286,     4287,     4288, ];  Here is the function: $('#postalSearch').click(function(){     var postalInput = $("#postalInput").val();     var postalInputSuffix = postalInput.match(/\d+/);     if( $.inArray(postalInputSuffix, baas) !== -1 ) {         alert('bestaat');     } else {         alert('bestaat niet');     } });  When I fill in 4288 and alert var postalInputSuffix it does output 4288 but I still get the message bestaat niet. Thanks for your time!

What is the most concise and efficient way to find out if a JavaScript array contains a value? This is the only way I know to do it: function contains(a, obj) {     for (var i = 0; i < a.length; i++) {         if (a[i] === obj) {             return true;         }     }     return false; }  Is there a better and more concise way to accomplish this?


I wish to create the animation of a robot on Blender and simulate the same animation in Webots to check for feasibility. For this, I'm thinking of extracting coordinate data from all objects in the scene into an external file ('.csv', for e.g.) using a python script. I wanted to create a simple scene initially and followed the tutorial here  to change cube position and create keyframes. I'm not sure how to get the coordinate data and save them on an external file. Any help would be greatly appreciated!

I'm working on a project that requires me to get some of the position and rotation values to give to an Arduino via pyserial, but after sifting through the Blender documentation I can't find how to get them through script.


Suppose that there are $n$ terms which are numbered from $1$ to $n$. We have to select any $r$ terms out of $n$. But there shouldn't be any two consecutive terms. In how many ways this can be done?  E.g: There are $30$ balls which are numbered from $1$ to $30$. We are commanded to select $5$ balls, but any two of them should not have consecutive numbers on them. In how many different ways can we do this?

In how many ways can we choose $r$ numbers from $\{1,2,3,...,n\}$,   In a way where we have no consecutive numbers in the set? (like $1,2$)


When I want to do something with a list I first check it if is not null or contains no elements (not to blow a foreach) and I usually use list.Any() but what is the best option - to use list.Count > 0 , or to use list.Any()?

in the System.Linq namespace, we can now extend our  to have the  and  extension methods.  I was told recently that if i want to check that a collection contains 1 or more items inside it, I should use the .Any() extension method instead of the .Count() > 0 extension method because the .Count() extension method has to iterate through all the items.  Secondly, some collections have a property (not an extension method) that is Count or Length. Would it be better to use those, instead of .Any() or .Count() ?  yea / nae ?


CREATE TABLE IF NOT EXISTS works on mysql but fails with SQL Server 2008 R2. What is the equivalent syntax?

I would like this to be the ultimate discussion on how to check if a table exists in SQL Server 2000/2005 using SQL Statements.  When you Google for the answer, you get so many different answers. Is there an official/backward and forward compatible way of doing it?  Here are two possible ways of doing it. Which one among the two is the standard/best way of doing it?  First way:  IF EXISTS (SELECT 1             FROM INFORMATION_SCHEMA.TABLES             WHERE TABLE_TYPE='BASE TABLE'             AND TABLE_NAME='mytablename')     SELECT 1 AS res ELSE SELECT 0 AS res;   Second way:  IF OBJECT_ID (N'mytablename', N'U') IS NOT NULL     SELECT 1 AS res ELSE SELECT 0 AS res;   MySQL provides the simple   SHOW TABLES LIKE '%tablename%';    statement. I am looking for something similar.


Windows 10.  Taking screenshots via "X-keys programmable usb keypad".  These are stored in a specific folder.  Later we add these screenshots to a report that is sent via e-mail.   Problem is; we are talking 10-20-30 pictures and with the relatively big file sizes, we can't send them via e-mail.   We can't edit them on the go, only at the end of the day. Image resize online works pretty well at reducing file size without losing too much quality. But it's cumbersome and we don't always have good internet connection. Here is the question ;   We need a way to batch resize the images easily and fast. Several different people will use this computer, so "easy" is key. What is the best way ?  A standalone image resize application?  Is there some script you can run i.e "reduce all images in folder "xxx" to 50% size" ?

Changing quality of the JPEG when saving an image, changes the file size. For eg. I have the following image. Dimension: 243px x 53 px Quality:100% File Size:9.7kb Background:      If I edit the image, keeping the dimensions and Quality same, the file size still falls to 6.1kb.      Problem: I am using Fotoresizer, which has a batch Quality change option, but due to the above problem, you cannot predict file size from quality alone. So when I batch change quality of a set of 200px x 300px images set at 20% quality, some files will turn out at 6kb, whereas others will turn out at 15kb, when the file size I want is 10kb.  Is there any program or programmable solution, which lets me save all files in a range of 10-11kb, without me manually changing the quality slider to change file size each time.


Is it possible for a hash function, SHA256 for example, to be a cyclic hash function, where the hash of the hash returns the original value? Example: SHA256(a) = b SHA256(b) = a  Or in another form: SHA256(SHA256(a)) = a  A math example would be f(x) = 1/x  because f(5) = 1/5, and f(1/5) return the original 5. f(f(5)) = 5.

I have a double-SHA-256 of some text $$ h_2 = \operatorname{SHA256}(\operatorname{SHA256}(m)).$$ I don't need the plain text ($m$), but somehow I need to get first $$h_1 = \operatorname{SHA256}(m).$$  Can I have it ($h_1$) by keep hashing the second one ($h_2$)? $$ h_1 = \operatorname{SHA256}(\operatorname{SHA256}(...\operatorname{SHA256}(h_2)...)).$$


I have a linear program: minimise $f^T x$ with equality and inequality constraints.  This does not have a unique solution, so I would like to find the solution of this that also minimises $g^T x$.  One approach to doing this is to solve a second linear program with the additional constraint $f^T x = f_{min}$.  In my case, it seems that finding this second minimum takes significantly longer than finding the first.  Is there any way of expressing this process as a single linear program?  Or any other better way of tackling the problem?

I had the following question on my last Algorithms test which I didn't know how to solve, and the the professor didn't agree to publish the solution. I would like to know the solution though, since it's been bothering me not knowing.  I am given two linear programs with the same variables- $P_1, P_2$, both in standard form and it is known that $P_1$ has an optimal solution. Write a single linear program for the following problem: Find among all optimal solutions to $P_1$ which satisfy the restrictions of both $P_1,P_2$, a solution that maximizes the objective function of $P_2$.


I am given the following question : Let $G$ be a finite group and $\chi$ an irreducible character. What is $\sum_{g\in G}\chi(g)?$ This is the sum of a row of the table character. I know the orthogonality relations but I never read that the sum of the rows in a character table are something particular.

If $\chi$ is a nontrivial irreducible character of $G$ (a finite group), define $S_{\chi}:= \sum_{x \in G} \chi(x)$. In terms of conjugacy classes $\mathcal{C}$, this is $\sum_{\mathcal{C}} |\mathcal{C}| \chi(\mathcal{C})$. Is there a nice condition that guarantees $S_{\chi}=0$?  I've noticed that this occurs, for instance, with $S_5$. I'd love a description of this phenomenon and a proof, if possible.


I have a SQL server DB for credit card processing system with 5 Tables  MerchantContract  PaymentKey   NVARCHAR(50) ProcessingID INT   DealTrace  Status       NVARCHAR(250) Tag          NVARCHAR(MAX)   DealSummmary  RefNumber    NVARCHAR(100) DealAuthCode NVARCHAR(100)   Processing  Name         NVARCHAR(50)   And Deal with whole bunch of fields of which the most important one are   OriginalOrderId  NVARCHAR(50) MerchantContract INT Amount           INT   Currently I'm querying these tables with such query:  SELECT  d.id,          d.date,          d.ip,          d.panmask,          d.merchantorderid,          d.amount,          d.cardholder,          d.bankhumanname,          d.cardtypeid,          d.bankcountrycode,          d.usercountrycode,          mc.paymentkey as merchantname,          dt.status,          d.merchantcontract,          dt.tag,          d.originalorderid,          ds.refnumber,          ds.dealauthcode,          mc.processingid,          pc.Name as processing,          d.customparams  FROM Deal as d  LEFT JOIN MerchantContract as mc ON mc.Id = d.MerchantContract  LEFT JOIN DealTrace as dt ON d.Id = dt.DealId  AND dt.id = (SELECT MAX(id) FROM DealTrace WITH (nolock) WHERE DealId = d.id)  LEFT JOIN DealSummary ds ON d.Id = ds.DealId  AND ds.id = (SELECT MAX(id) FROM DealSummary WITH (nolock) WHERE DealId = d.id)  LEFT JOIN Processing pc on mc.ProcessingId = pc.id WHERE (d.MerchantContract IN ('13'))  ORDER BY ID desc OFFSET 0 ROWS FETCH NEXT 1000 ROWS ONLY   However for each MerchantContract there might be several rows with OriginalOrderId but different values in other columns. For example  MerchantContract|OriginalOrderID|Status|Amount|... 3|13_Qrta|charge|101|... 3|13_Qrta|refund|94|... 4|15_Utq1|charge|56|...   I would like for each unique pair of MercahntContract OriginalOrderId aggregate data in one row, so above resuklt would look like  MerchantContract|OriginalOrderID|Status|Amount|... 3|13_Qrta|charge,refund|101,94|... 4|15_Utq1|charge|56|...   I was looking around but unfortunately couldn't find solution. I was trying to modify first FROM to   SELECT ... (SELECT * FROM Deal d1 WHERE d1.Id=(SELECT MAX(Id) FROM Deal d2 "+     "WHERE d2.OriginalOrderId=d1.OriginalOrderId)) d  LEFT JOIN ...   But it didn't give the required result. Would really appreciate if anybody could give any hints as to how go about my problem.

Let's say I have a table of employees, like this:  Name     Sex     Role  Bob      M       Developer Joe      M       QA   Now, I have a problem with duplicated rows in this table. I will fix it sometime but it's not the issue. What I currently need is something that queries such a table:  Name     Sex     Role  Bob      M       Developer Bob      M       Janitor Joe      M       QA Joe      M       CEO   And will output the following rows:  Name     Role  Bob      Developer, Janitor Joe      QA, CEO   It doesn't matter to me if the "Role" will be split to separate columns or be a single column with multiple values.  Using SQL Server 2008 if it matters.


I'm currently trying to figure out primary ideals and I think I proved the following geometric statement, but I'm not sure if I did it right and would like to have some feedback.     Lemma: An ideal $\mathfrak{a}$ of a commutative ring $A$ is primary if and only if $\text{Spec}(A/\mathfrak{a})$ is irreducible.   Proof: First note that $\text{Spec}(A/\mathfrak{a})$ is irreducible if and only if $\sqrt{(0)} \subset A / \mathfrak{a}$ is a prime ideal. Now suppose $\mathfrak{a}$ is primary, and $\bar x \cdot \bar y \in\sqrt{0} \subset A / \mathfrak{a}$. Then $x^n\cdot y^n = (xy)^n \in \mathfrak{a}$ for some $n \in \mathbb{N}$, so either $x^n \in \mathfrak{a}$ or $(y^n)^m \in \mathfrak{a}$ for some $m \in \mathbb{N}$. I.e. either $x \in \sqrt{(0)}$ or $y \in \sqrt{(0)}$.  Conversely, suppose $x \cdot y \in \mathfrak{a}$. Then either $x$ or $y$ is nilpotent modulo $\mathfrak{a}$, i.e. $x^n \in \mathfrak{a}$ or $y^n \in \mathfrak{a}$.  I'm still not 100% sure that I'm done here, because I only have $x^n \in \mathfrak{a}$, not $x\in \mathfrak{a}$. Am I missing something, or is the claim wrong? If so, I would like to see a counterexample.

Let $A$ be a commutative unital ring, and let $\mathrm{Spec}(A)$ be it's set of prime ideals endowed with the Zariski Topology.   In this topological space, my text had me prove a couple facts, specifically:        $\{X_a \colon a \in A\}$ forms a basis for the topology, where $X_a = \{ x \in \mathrm{Spec}(A) \colon a \notin x\}$   $X_a \cap X_b = X_{ab}$   $X_a = \emptyset \iff a$ is nilpotent in $A$      I have a conjecture that $\mathrm{Spec}(A)$ irreducible implies that every zero-divisor is nilpotent. The definition I have of irreducible is      $\mathrm{Spec}(A)$ is irreducible if every two non-empty open sets   have a non-empty intersection.   I thought I successfully proved my claim, but after review I think I actually proved a weaker claim (technically a stronger claim, depending on how you look at it). Here is my attempted proof.     Proof: Suppose $z \in A$, $z \neq 0$, and $zy = 0$, for some $y \neq  0$. Proceeding by way of contrapositive suppose $z$ is not nilpotent.    Then by fact 3 above we have $X_z \neq \emptyset$, but $X_z \cap X_y =  X_{zy} = X_0 = \emptyset$. Thus $\mathrm{Spec}(A)$ is reducible.   It appears to be an obvious flaw that I do not make an assertion about whether or not $y$ is nilpotent. Therefore the claim I actually proved is      If $\mathrm{Spec}(A)$ is irreducible and $xy = 0$, for non-zero $x$ and $y$, then one of $x$ or $y$ is nilpotent.    Upon inspection, this actually made sense because the text had me prove the characterization that $\mathrm{Spec}(A)$ is irreducible if and only if the nilradical is a prime ideal. With this characterization, if the nilradical is prime and $xy = 0$, since $0$ is in the nilradical then $xy$ is in the nilradical, and if the nilradical is prime then $x$ is in or $y$ is in. Which is consistent with what I proved, that atleast $\textbf{one}$ of $x$ or $y$ is nilpotent.  Obviously it is no such luck that one could prove if $xy = 0$ and $x$ is not nilpotent, then $y$ is not nilpotent, since we are not in an integral domain (otherwise my original claim would be vacuously true).  $\textbf{HOWEVER:}$ I still believe my conjecture to be true. I think either 1) I am overlooking something very obvious, a quick fix, or 2) In order to prove my original claim in full generality I might need more machinery than I have at my disposal right now. Some thoughts I had to try and get my claim proven were to  1. Consider when and why the nilradical is a prime ideal,  2. Consider the fact that the set of zero divisors is a union of prime ideals,  3. quit wasting time thinking about this and move forward in my text and maybe when I finish the book I will either realize why this claim is not even important and thus proving it is not a good use of time, or the proof will be obvious.   Any help, thoughts, opinions appreciated.    Edit: I should also mention that the reason I still believe my conjecture is true is not because I have some intuition (although I did check some specific examples), it is because I googled "when are zero divisors nilpotent" and found an answer to this question  that says the nilradical being prime as a sufficient condition for zero divisors being nilpotent. As mentioned the nilradical being prime is iff the spectrum is irreducible, thus my claim should hold.  Also can someone give me a counter example for why the converse does not hold? That is an example where the zero divisors and nilpotents coincide but the nilradical is not prime? There is probably a simple $\mathbb{Z}_n$ case that is apparent using elementary number theory but I don't have anything.


Im trying to update user image with php but im facing errors that $_FILES is not defined. Already is set but facing the same issue. I have tried to find in other answers here but its not working. File path is added on database without extension (example: photos/5f583778a818e.) but file is not moved to directory (folder). I appreciate your help!  Image Directory: dms>views>photos  public function updateuser(){       GLOBAL $conn;         if(@$_POST['first'] && (@$_POST['last']) && (@$_POST['filepath']) && !empty($_POST['filepath'])){         //if(@$_POST['first'] && (@$_POST['last']) && (@$_POST['filepath']){         //}               if($_SESSION['id']){                 $id = $_SESSION['id'];             }             $user = new UserModel();             //echo $id;             $user->first = trim($_POST['first']);             $user->last = trim($_POST['last']);             @$filetemp = isset($_FILES['filepath']['tmp_name']);             @$filename = uniqid(isset($_FILES['filepath']['name']));             @$filetype = end(explode('.', ($_FILES['filepath']['name'])));             $filename = $filename . '.' . $filetype;             $user->filepath = "photos/" . $filename;             move_uploaded_file($filetemp, $user->filepath);             //var_dump($_FILES);             //var_dump(is_dir('photos/')); check if folder is DIR                         $query = $conn->prepare("UPDATE users SET first = ?, last = ?, filepath = ?  WHERE id = '$id'");             $query->bindValue(1, $user->first);             $query->bindValue(2, $user->last);             $query->bindValue(3, $user->filepath);             $query->execute();              //print_r($_FILES);             echo "Updated";           }else{               echo "None";           }          }  Below is my html  <form method="POST" enctype="multipart/form-data">
<img id="previewImg"             src="views/<?php echo $user->filepath; ?>" alt="user-img"               class="rounded-circle mCS_img_loaded">             <input id="filepath" name="filepath" type="file" onchange="previewFile(this);" />
         <input type="submit" id="update" value="Update"  class="btn btn-primary waves-effect waves-          light">

     </form>  And my AJAX  $(document).ready(function () {       $('#update').click(function (e) {         e.preventDefault(); $.get('/myurl/')                  var first = $('#first').val()         var last = $('#last').val()      // var password = $('#password').val()       var filepath = $('#filepath').val()                  $.ajax({           url: 'profile/updateuser',           method: 'POST',           data: {             first: first,               last: last,                 filepath: filepath           },           success: function (data, textStatus) {             $('.result').html(data).show().delay(6000).fadeOut(300)           }         })       })     })

I would like to upload a file asynchronously with jQuery.     $(document).ready(function () {     $("#uploadbutton").click(function () {         var filename = $("#file").val();          $.ajax({             type: "POST",             url: "addFile.do",             enctype: 'multipart/form-data',             data: {                 file: filename             },             success: function () {                 alert("Data Uploaded: ");             }         });     }); });  File <input type="file" id="file" name="file" size="10"/> <input id="uploadbutton" type="button" value="Upload"/>     Instead of the file being uploaded, I am only getting the filename. What can I do to fix this problem?


Let $n>0$ be an integer. Consider all partitions of $n$, i.e. all possible ways of writing $n$ as a finite sum of positive integers,   $$n=n_1+n_2+\cdots+n_k.$$   What partition maximizes the product $n_1n_2\cdots n_k$?   Examples:   $2=2$ $3=3$ $4=2+2$ $5=3+2$ $6=3+3$ $7=3+2+2$ $8=3+3+2$ $9=3+3+3$ $10=3+2+2$ $20=3+3+3+3+3+3+2$ $30=3+3+3+3+3+3+3+3+3+3$ $40=3+3+3+3+3+3+3+3+3+3+3+3+2+2$ $50=3+3+3+3+3+3+3+3+3+3+3+3+3+3+3+3+2$      Conjecture: It is the partition that has the maximum number of $3$'s among those consisting only of $3$'s and $2$'s.

Suppose we have a natural number $n \ge 0$.  Given natural numbers $\alpha_1,\ldots,\alpha_k$ such that   $k\le n$ $\sum_i \alpha_i = n$   what is the maximum value that $\Pi_i \alpha_i$ can take?  I'm quite sure that there is a theorem telling me the result, but I cannot find it. For sure an upper bound is $n^k$ but I'm searching for a real upper bound. I'm pretty sure that upper the bound should be $n^2$, but I don't know I could prove it.


Let $V$ and $V'$ be vector spaces over a field $K$. A  $$f:V \to V'$$ is a mapping which preserves addition and scalar multiplication.  My question is: what is the difference between linear mappings and linear functions?

I wonder if there is any difference between mapping and a function. Somebody told me that the only difference is that mapping can be from any set to any set, but function must be from $\mathbb R$ to $\mathbb R$. But I am not ok with this answer. I need a simple way to explain the differences between mapping and function to a lay man together with some illustration (if possible).  Thanks for any help.


When saying goodbye and thank you after hosting something, it is common to say something like "I have been your host" or "I, person X, have been your host" BUT, would it also be correct to simply say "I have been person X" Even though one does in fact continue to be person X after the event has ended?  I have seen examples of this  (Stephen Fry to be more precise), but is it a correct use of grammar?  The wording was: "You have been watching QI, I have been Stephen Fry. Thank you and good night!"

We went to an electronics showroom, where we chatted with a sales girl. She explained some technical stuff about the things we were interested in. When she had finished explaining, she said      "By the way, I have been Jessica."   This usage is not new to me: it's pretty common in the US, and in Hollywood movies. But I have always wondered about how it could be correct (if indeed it is). I understand what it means, I just don't see it as grammatical. What is the logic of taking it as grammatical?  You have been Jessica. So what are you now?   A lot of people in the comments are saying that they never heard nor saw anyone using this line to tell their name. Here is an example:    at 00:25


I am pretty new in JavaScript and I have some doubts related to the variable scope.  So I tryed to do this example:  function outer() {      alert("INTO outer()");     var val1 = 1;      inner();      alert(val2); }  function inner() {     alert("INTO inner()");      val2 = 2;   }  outer();   In this simple example the outer() function is perform, in this function I call the inner() function that declare and initializes the val2 variable. Then come back to the outer() function and from here I access and print the val2 value.  So it seam to me that in Javascript I can access to the variable defined in the inner function from the outer function but I can't access to the variable declared in the outer function from the inner function.  Is it true? If it is true why this choose?

What is the scope of variables in javascript? Do they have the same scope inside as opposed to outside a function? Or does it even matter? Also, where are the variables stored if they are defined globally?


My system not showing the upgrade button in the software updater window.h\How can I upgrade to newer version?

What are the different ways I can use to upgrade Ubuntu from one release to another?


In Hirsch's Differential Topology, he defines a smooth manifold $M$ to be reversable if it is orientable and admits an orientation-reversing diffeomorphism. I feel confused since I believe that any orientable manifold should admit one such diffeomorphisms. Are there any counter-examples for this?

Why each sphere admits an orientation reversing diffeomorphism onto itself? (For even dimensional ones can we take conjugation map?) And why complex projective spaces do not admit? Is there a geometric way to see this without using characteristic classes?


I have lately become very interested in testing and Im now trying to learn to do unit testing in the best way possible. I use NUnit together with Rhino Mocks. I have also been reading a lot over here at Stackoverflow but havent been able to find a clear answer to my question.  What I wonder is if I have a method like the below, should I mock the OfficeClass dependency and also test GetAllOffices or only use a stub for the dependency and verify that the method GetAllOffices has been called and that I indeed get the offices back that I expected from my  setup for the stub?  public Offices GetAllOffices()  {     try     {         var offices = officeClass.GetAllOffices();         return offices;     } }   Will it make any difference if the OfficeClass is just another POCO or if it is let say a web service in sence of mocking vs stubbing?  Long question short: When to Mock and when to Stub in unit testing?

I haven't play enough with this and usually use mocks, but I wonder what are the differences between this two and when to use one or the other on Rhino Mocks.  Update:  I also found the answer to my question in :  The difference between stubs and mocks You can get the actual definition of the these terms in this article: . I want to focus on the difference from the point of view of Rhino Mocks.  A mock is an object that we can set expectations on, and which will verify that the expected actions have indeed occurred. A stub is an object that you use in order to pass to the code under test. You can setup expectations on it, so it would act in certain ways, but those expectations will never be verified. A stub's properties will automatically behave like normal properties, and you can't set expectations on them.  If you want to verify the behavior of the code under test, you will use a mock with the appropriate expectation, and verify that. If you want just to pass a value that may need to act in a certain way, but isn't the focus of this test, you will use a stub.  IMPORTANT: A stub will never cause a test to fail.


§2, exercise 5, p.17:     Let $A_1,\dots,A_n$ be events, and define $S_0,S_1,\dots,S_n$ as   follows: $S_0=1$   $$\begin{alignedat}{1}\begin{split}S_{r}=\sum_{J_{r}}P\left(A_{k_{1}}\cap\cdots\cap > A_{k_{r}}\right),\end{split}  & 1\leq r\leq n\end{alignedat}$$ where   the sum is over the unordered subsets   $J_{r}=\left[k_{1},\dots,k_{r}\right]$ of $\left\{ 1,\dots,n\right\}$   .      Let $B_m$ be the event in which each of the events $A_1,\dots,A_n$   occurs exactly $m$ times. Show that   $$P\left(B_{m}\right)=\sum_{r=m}^{n}\left(-1\right)^{r-m}C_{r}^{m}S_{r}$$   I don't understand what $B_m$ is!? (my understandings lead to wrong result, tested with particular values of $m$, and $n$)  The original Russian texts:     Пусть $B_{m}$ - событие, состоящее в том, что одновременно произойдет в точности $m$ событий из $A_{1},\dots,A_{n}$.   What is the Russian texts actual meaning? (I want to know if there was problem with translation or it's my fault)  I found an answer from a , which said that:     (google translator): This is indeed a bit incomprehensible, because here m * n events are combined into one   but, I don't know how to interpret the question like that.    P/S: I found an answer, my question could be marked as duplicated:   Indeed, I found that the combined result of the online translators (Google, Yandex, Bing, PROMT) is closed to the exercise posted in the link above:     machine translation: Let $B_{m}$ be the event, which consists simultaneous occurrence of exactly $m$ events of $A_{1},\dots,A_{n}$

For $1\le i_1,i_2,...,i_k\le N$ denote    $$p_{i_1,...,i_k}=\Pr(A_{i_1}\cap A_{i_2}\cap\dots\cap A_{i_k}),$$   $$S_k=\sum\limits_{1\le i_1\le\dots\le i_k\le N}p_{i_1,\dots,i_k}.$$      Show that the probability $P_{[m]}$ that exactly $m$ among the $N$ events $A_1,\dots,A_N$ occur simultaneously is given by    $$P_{[m]}=S_m-\binom{m+1}{m}S_{m+1}+\binom{m+2}{m}S_{m+2}-\dots (-1)^{N-m}\binom{N}{m}S_{N}.$$   We've already proven the inclusion exclusion formula: $$\Pr\left(\bigcup\limits_{i=1}^NA_i\right)=S_1-S_2+S_3-\dots (-1)^{N-1}S_N,$$  but the problem is the factors $\binom{m+1}{m}...$ before $S_i$'s, I cannot really show that.


I'm following  and I've found something I don't clearly understand. Following code defines a named function expression:  var ninja = function myNinja(){   console.log(myNinja); // function myNinja() {...} }; myNinja; // undefined   As I can see, in the current scope (suppose it's global), ninja is the variable that holds reference to the named function myNinja. ninja variable is accessible in the scope - that's clear, but myNinja is not accessible in the scope (but it's accessible inside its own function). How come?  If I define a function (not using a function expression, but function declaration):  function Cheese() {   console.log(Cheese); }   then it's accessible in the current scope. I know that this just works like that - but can someone explain why is that?

I've recently started maintaining someone else's JavaScript code. I'm fixing bugs, adding features and also trying to tidy up the code and make it more consistent.  The previous developer used two ways of declaring functions and I can't work out if there is a reason behind it or not.  The two ways are:  var functionOne = function() {     // Some code };     function functionTwo() {     // Some code }   What are the reasons for using these two different methods and what are the pros and cons of each? Is there anything that can be done with one method that can't be done with the other?


How can I enlargen the fins and ribcage of the fish below?  I need to 3D print the model but currently at the moment the peices are too small to print or they snap off after being printed!!!I just need to make them thicker so that this wont happen.

This hand looks too skinny. What is the simplest way to make it fatter, especially the fingers?


I have my Minecraft account and I accidentally deleted the launcher so I downloaded it again and I had to login again. I put in my password and my e-mail, my e-mail was right but my password wasn't, I played on this account for years and I even wrote my password on paper so I'm certain it's correct. I tried to migrate and it said that there was a Mojang account already so the password was correct.

I tried to log into Minecraft today to find that my password isn't working. I tried to change it, but I can't login to my email because I forgot the answer to my security question. I tried changing the email to a different one, but that didn't work for some reason (it kept saying "invalid email"). I don't have my transation ID because I forgot which credit card I used.  Does this mean that I have to buy a new Minecraft account?


I an trying to implement normal mapping in opengl es for which i need the per vertex tangent data. Is there some means to get that from python blender api

Suppose you have a mesh; you go into Edit mode,  set Transform Orientation to Normal,  show 3D manipulator widget, Pivot Point = Active Element, face select mode, and then you select any one face: immediately you will see a blue arrow representing the face normal, and also a red and a green arrow representing the face's tangent and bitangent.  What is the most straightforward way to refer  to said tangent and bitangent vectors from a Python script? The API documentation confuses me with loops and uv's, yet, clearly, Blender assigns a tangent and bitangent to each face without hesitation!


I found out that male customization sucks in X/Y, so I'd like to start over as a female character.   However, I got Absol from Wondertrade and I'd like to keep it on the new save. I know that you can use Pokemon bank, but my family doesn't allow me to "buy" it. So my question is how can I do so without Pokemon Bank?

I've been considering restarting my save and replaying the story with access to the entire National Pokedex (Minus a few Event-only Pokemon I'm missing) from the start. But I would first like to confirm: Can I withdraw my stored Pokemon from the bank if my game is reset? It seems that the only contributing factor is that I end up signed in with the same Nintendo Network ID, so as long as my network ID remains the same, I can withdraw stored Pokemon regardless of what save-game or cartridge is in my system, correct?  While I'm reasonably confident it works the way I think it does, past experience (My Pokemon Ranch being tied to specific trainer IDs, and something about the dream world being tied to the game's wireless settings) has made me just cautious enough to ask before attempting.


I need help with this excercise.     If $\gcd(m,n) = 1$, then $\gcd(m+n,mn ) = 1$.   I don't know how to prove this, I know the definition of $\gcd$ but I can't prove it.

Let $a$ and $b$ be two integers such that $\left(a,b\right) = 1$. Prove that $\left(a+b, ab\right) = 1$.   $(a,b)=1$ means $a$ and $b$ have no prime factors in common  $ab$ is simply the product of factors of $a$ and factors of $b$.  Let's say $k\mid a+b$ where $k$ is some factor of $a$.  Then $ka=a+b$ and $ka-a=b$ and $a(k-l)=b$.  So $a(k-l)=b, \  a\mid a(k-1)$ [$a$ divides the left hand side] therefore $a\mid b$ [the right hand side].  But $(a,b)=1$ so $a$ cannot divide $b$.  We have a similar argument for $b$.  So $a+b$ is not divisible by any factors of $ab$.  Therefore, $(a+b, ab)=1$.  Would this be correct? Am I missing anything?