I suggested using which to confirm whether a command works only as a .  cd is an example of a command that works as a shell builtin.  It would be much harder to implement the same function as a binary...  So why does my Fedora system have a binary /usr/bin/cd?  It doesn't implement the magic necessary to affect the shell (parent process) working directory, to match the behaviour of the cd builtin.  My Debian 8 system doesn't have /usr/bin/cd.  $ command -v sudo /usr/bin/sudo $ command -v cd cd $ which sudo /usr/bin/sudo $ which cd /usr/bin/cd $ rpm -q --whatprovides /usr/bin/cd bash-4.3.43-4.fc25.x86_64 $ (. /etc/os-release && echo $PRETTY_NAME) Fedora 25 (Workstation Edition) $ pwd /home/alan $ cd /home && pwd /home $ /usr/bin/cd /home/alan && pwd /home $ cd --help bash: cd: --: invalid option cd: usage: cd [-L|[-P [-e]] [-@]] [dir]   The full list of binaries provided by the bash package is     $ rpm -q --dump bash|grep /usr/bin|cut -f 1 -d ' '|cut -f 4      alias   bash   bashbug   bashbug-64   bg   cd   command   fc   fg   getopts   hash   jobs   read   sh   type   ulimit   umask   unalias   wait

As referenced in , POSIX systems have an external binary cd in addition to the shell builtin. On OS X 10.8 it's /usr/bin/cd. You can't use it like the builtin cd since it exits immediately after changing its own working directory. What purpose does it serve?


When on feed mode, tapping on any hot question (top line with big blocks) is not working. Nothing happen.     App Version: 1.6.0.10 Device: iPad Air 2 (Wi-Fi) OS Version: Version 10.0.2 (Build 14A456)

App Version: 1.6.0.10 Device: iPad mini 2G (Wi-Fi) OS Version: Version 9.3.5 (Build 13G36)   Just updated (to 1.6.0.10) and the hot question links no longer work. They highlight as if selected but do not open the question.  "Recent" question links still work.  I've tried    closing and reopening the app; force rebooting the iPad (hold home/power until second apple logo displays);   deleting and reinstalling the app upgrading from iOS 9 to iOS 10   No joy.  This bug does not occur on an iPhone 4s running iOS 9.3.5 and the SE app 1.6.0.10.  Prior to tapping on a hot question    After tapping on the leftmost hot question-note the color change but the question does not open.


I am new to ubuntu. I downloaded the iso file but when I open it - it opens a virtual cd drive instead of installing on my USB - I need help. detailed help. my pc is windows 10. thank you

I would like to see a full how-to guide on how to install Ubuntu.


I'm requesting help regarding to the best method/function to parse a string AFTER, it as been already, by the parameters.  I have a many, many lines of MySql already in place, the prepare statement methods to avoid SQL injections are out of the question, because i don't have the time. Is there any function to parse scape characters on a string, right before i call:  //$sql_query_string_CLEAN = THE PLACE THE PARSING FUCNTION($sql_query_string);     mysql_query($sql_query_string_CLEAN, $connection);

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


My Windows Server is running on 3gb of memory right now, and I would like to upgrade to 16gb.  However, I don't know what type of memory to buy.  I know that the notches in the physical RAM are different depending on the memory type.  Is there a way in Windows Server 2012 to detect the type of memory so I get the correct one?

I have to upgrade the RAM on 8 different desktop PCs - each of them with varying specs, different ages, different manufacturers, different motherboards, etc. I'm pretty sure they don't all use the same type of RAM.  I've been doing some Googling, and just can't wrap my head around how to determine what type of RAM I will need. I think the main issue is that I don't understand what the different types of RAM are (DDR, DDR2, DDD3, PC400, PC3200), the different speeds, the different physcial sizes (160 pin, 184pin, etc), SIMM, DIMM, DRAM, SDRAM, dual channel, single channel, etc. If you consider the many different permutations that the above can result in, you will understand my predicament.   Is there are good website/online resource that explains modern RAM (ONLY the last 5 years), without explaining all the way back to the 1990s, 1980s or even earlier. Is there are free tool that I can download to help me determine what type of RAM I need to purchase? Is there any other advice/suggestions that could be useful/helpful for me to get past this problem.


I accidentally didn't refrigerate a package of ground Italian sausage when I returned from the grocery.  It sat out at room temp for almost 3 hours.  How safe should I assume it is?

If I left food out of the refrigerator for some period of time, is it still safe? If I left it out too long, can I salvage it by cooking it more?


Running 4.4.2 KitKat. Does the OS really take up 7GB? I've only got like 5 games downloaded and already running out of space for apps. :(

I have an HTC Wildfire (the original, not the S version). It is supposed to have 512MB of memory. When I check my free space in the app manager I noticed I have around 185MB. Why is this?  I am using CyanogenMod which is around 80MB, if this wasn't accounted for there is still a lot of space missing. Why is my phone reporting so little?


Years ago i installed ubuntu on a hard drive in my computer. A few days ago, after the release of 18.04, i bought a ssd and reinstalled everything on that. The old hdd is still linked in the computer - just to look up things.  GRUB does index the old hdd as secondary boot option. But i will never ever boot the old system again. So is there any way to remove the old hard drive from the grub options?

I installed Fedora 15 on my laptop and deleted XP (at least I think XP is deleted).  Then I installed Ubuntu as dual boot with Fedora 15.  Now I want to remove Fedora 15 and leave only Ubuntu (and XP if it is still available).  Can anyone help with the steps to uninstall Fedora?  Please give me simple steps to follow, I'm a nooby.  Thanks!


just want know how to Order folders like they looking in my Explorer folder Sorted by name .. It's looks like :::  So i tried use this :::  DirectoryInfo sourcreInfo = new DirectoryInfo(SourcePath);                 DirectoryInfo[] sourceFolders = sourcreInfo.GetDirectories().OrderBy(p => p.Name).ToArray();  but for sure it's not working ... not sorting and in addition it needs addition memmory ... imagine i have in my folder 1000 reports ... soo ... here how i worked with this sourceFolders:: reportDir is just List   foreach (DirectoryInfo report in sourceFolders)                 {                   reportDir.Add(Path.GetFileNameWithoutExtension(report.Name)).ToString()));                       }  Guys waiting for any proposition how to get Ordered by Name Directories ... To make this operation correctly .. :) Really what in result i getting using DirectoryInfo ::::  I expected :: report1, report2 , report3 , report4 , report5 .... by numbers, like shows in explorer picture

Anyone have a good resource or provide a sample of a natural order sort in C# for an FileInfo array?  I am implementing the IComparer interface in my sorts.


I have 1 abstract class: Model<E> with 2 implementations: ItemModel and ItemLogModel. The constructor of ItemLogModel is protected, but it is still accessible from ItemModel. I expect the protected constructor to only be accessible by subclasses of ItemLogModel. Can someone explain to me why this is possible?  Code:  public abstract class Model<E> implements IModel {     private final Repository<? extends IModel, E> _repository;     protected E _entity;      protected Model(Repository<? extends IModel, E> repository, E entity)          this._repository = repository;         this._entity = entity;     }             ... }  public class ItemModel extends Model<Item> implements IItem {     ...      @Override     public void setStatus(Status status, String logMessage) throws Exception {         super._entity.setStatus(status.toString());         super.update();          // CALLING protected constructor here!         new ItemLogModel(this, logMessage);     } }  public class ItemLogModel extends Model<ItemLog> implements IItemLog {      protected ItemLogModel(ItemModel itemModel, String message) throws Exception {         super(REPOSITORY, new ItemLog());         super._entity.setAccessPointBean(itemModel.getEntity());         super._entity.setStatus(itemModel.getStatus().toString());         super._entity.setMessage(message);         super.save();     }  }

In Java, are there clear rules on when to use each of access modifiers, namely the default (package private), public, protected and private, while making class and interface and dealing with inheritance?


I have one problem, I have a javascript function which I want to use when the browser is closed, How can I detect that a browser is being closed?    I have made some research on that I got solution like onunload or beforeunload but both the functions are being executed when I am reloading the page, Is there any solution that I can differentiate reload and browser/tab close.

When we refresh the page (F5, or icon in browser), it will first trigger ONUNLOAD event. When we close the browser (X on right top icon),It will trigger ONUNLOAD event. Now when ONUNLOAD event is triggered, there is no way to distinguish between refresh the page or close the browser.   If you have any solution then give me.


I'm not looking for any derogatory term, but for something that the woman herself would say  Example:     He was a good guy. Not sure why I was so sure of that. Maybe it was a   skill that I developed when I was a [...].

What's the feminine version of womanizer?


I understand that there is no current workaround known for having two Apple Thunderbolt Displays run on an Apple Silicon Mac with a M1 Processor. I am opening this thread for creative solutions. Please let me know if you find a way to make this work - whether through a dock, or daisy chaining, or a Blackmagic HDMI/Thunderbolt converter. Thanks!

The Apple Silicon based  supports Thunderbolt version 3 and I'm wondering if anyone has tried connection one to an ? Of course you'd need to use one of Apple's Thunderbolt 3 to Thunderbolt 2 converters. I also understand that this version is limited to supporting only a single 4K or 6K display, but since the original Apple Thunderbolt Display is only 2K I’d want to try and daisy chain these. Can I run more than one external display from the Apple Silicon M1 CPU/GPU based MacBook Pro (or Air)?


I feel like I'm doing some noobish overlooking of things. Can anyone help me understand why the following doesn't work  ["1.1", "2.2", "3.3"].map(parseInt); //=> [1, NaN, NaN]   This works though ???  ["1.1", "2.2", "3.3"].map(function(num) {   return parseInt(num); }); //=> [1, 2, 3]   This seems to work too  ["1.1", "2.2", "3.3"].map(Number); //=> [1.1, 2.2, 3.3]

From the :  [1,4,9].map(Math.sqrt)   will yield:  [1,2,3]   Why then does this:  ['1','2','3'].map(parseInt)   yield this:  [1, NaN, NaN]   I have tested in Firefox 3.0.1 and Chrome 0.3 and just as a disclaimer, I know this is not cross-browser functionality (no IE).  I found out that the following will accomplish the desired effect. However, it still doesn’t explain the errant behavior of parseInt.  ['1','2','3'].map(function(i){return +i;}) // returns [1,2,3]


How should I refer to things that are necessarily to be in pair but they are as one, such as pants, trousers, tweezers, scissors, glasses? Should I refer them as singular or as plural in the sentences as follow:      "This is a beautiful pants"      "This are beautiful pants"?      This is the best tweezers that you can have.      These are the best tweezers that you can have.      It is a nice glasses.      They are nice glasses.

My glasses (was/were) lying on the table.   My trousers (is/are) torn.   (This/These) binoculars (was/were) gifted to me.      I know they're in plural form, but plural nouns such as rickets, measles are disease names, but they take singular verb.


I have Windows 10 (Build 14295) Pro. How to disable Lock Screen? I googled it, but there is no solution.   I tried . It does not work for me.

I would like to configure this windows 10 machine to not ask for a password when resuming from IDLE, but still ask for a password when resuming from STANDBY or HIBERNATE.  The screen needs to turn off after 5 minutes and NOT use a screen saver.  The only information I can find is about disabling the lock screen password entirely - which is not what I want. Whether the lock screen continues to show or not is relevant as long as it doesn't require a password.  Version is Windows 10 Pro. It is also connected to a SBS2011 domain.


I am trying to run a check to see if a string is just white space. I tried using trim like this:  if( dataIn[ i ].trim() == "" )     {         throw new MailRecordException( "Line: " + lineNumber + ", Field: "             + fieldNumber + " :Blank Field" );     }   But it never registers as true. How could I run a check to see if a string is only whitespace?

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?


How can I change the default program for a file without changing its icon? For example, I'd like some file extensions (.css, .js, .cshtml, etc.) to be opened with , but I want to keep the original icon that MS Visual Studio has set.

Let's say I want to open XML files in Notepad, I can change the default program through Control Panel > Programs > Default Programs > Associate a file type or protocol with a program.   However, that will also change its default icon to that of a text file. If I repeat the process for other file types then I lose the ability to easily distinguish different files in a folder based on their icon.  So after I change the default program, I would like to 'roll back' the icon change.   HKEY_CLASSES_ROOT\xmlfile\DefaultIcon stays the same as before the default program changed: %SystemRoot%\System32\msxml3.dll,0  I tried adding HKEY_CURRENT_USER\Software\Classes\xmlfile\DefaultIcon, as well as HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.xml\DefaultIcon but neither seem to work.  What registry key(s) should I change to get back the old icon (%SystemRoot%\System32\msxml3.dll,0) but keep Notepad as the default program?  I downloaded  and it shows %SystemRoot%\System32\msxml3.dll,0 as the default icon for XML files, even though that is not the icon I see in Explorer, and even in FileTypesMan itself!


How can I un-vote the comment that I voted it earlier? It seems only possible in the first couple of seconds.

As mentioned on :     For something that can be done so   easily by accident, there should be   the ability to undo mistakes.   I know that I have clicked several times on a comment up-vote without actually wanting to.  I would suggest being able to cancel the up-vote (maybe only for a couple of minutes or even less than a minute, no problem, as long as I can undo a miss-click).


Why the ball is not round on following crop:    SS = 1/60  What's going on?

In answer to , Adam Davis writes:     Your camera complicates this by using   a rolling shutter above a given speed   (usually around 1/200. This means that   only a portion of the image sensor is   exposed to the scene at any given   time, so if the light changes during   the exposure, the color change will   only affect a portion of the image   sensor.   Rolling shutters often are also mentioned in the .  However, I am yet to see a discussion of what a rolling shutter is, how it works and when it is important.  What is a rolling shutter?  What are the implications of using one for my photos?


Does there exist a function $f:\mathbb{R} \rightarrow \mathbb{R}$   satisfying $f(1) = 1$, $f(-1) = -1$ and $$|f(x)-f(y)|\leq|x-y|^{3/2}$$ $\forall x,y\in\mathbb{R}$?   I tried polynomial functions, $\sin(\frac{\pi}{2}x)$ etc. None is fitting the third condition. In competitive exams, searching for functions is a bad idea. Can anyone give advice? What should I do when I get this type of question? How to prove or disprove? Please explain.

I want to show that if a function $f:[a,b]\rightarrow \mathbb R$ satisfies a Hölder condition of order $\alpha > 1 $ then it is constant.  The way I think of it is as follows:  $$|f(x) - f(y)| < K|x-y|^\alpha$$  $$\frac{|f(x) - f(y)|} {|x-y]}  < K|x-y|^{\alpha -1}$$  $$\lim_{y\rightarrow x} \frac{|f(x) - f(y)|} {|x-y]} \le \lim_{y\rightarrow x}  K|x-y|^{\alpha -1} =0 $$ As the limit is $0$, we can remove the modulus, so we get:  $$\lim_{y\rightarrow x} \frac{f(x) - f(y)} {x-y} = 0$$ So $f$ is derivable and $f'(x) = 0$ for all $x$ in $[a,b]$. Note that the reason we can add the limit $y\rightarrow x$ is because $[a,b]$ is closed in $\mathbb R$.  However, the question gives as a hint using the mean value theorem. I am not sure why one should do that. You would first have to prove that $f$ is derivable in a similar manner to what I did, and then prove that $f$ is constant. Or is there a simpler way to do it and I am missing it?  Also please inform me of any mistakes I did in the proof (if any)/ Thank you!


Just by plugging in numbers, I know that there are 4 solutions: X = 1, 3, 5 and 7. I'm not sure if I need to show additional steps or if I can just write my answer as it is.

Prove that if n is an odd positive integer , then $n^2\equiv1\mod8$.  Can I prove by counter example by inserting several odd numbers?  My work: I insert 1 into n. $8\mid(1^2 - 1) \implies 8\mid0$ I insert 3 into n. $8\mid(3^2 - 1) \implies 8\mid8$


I installed Master PDF editor 4 from a .deb file downloaded from the official webpage on Ubuntu 16.04. The installation via Software was successful without any error message. However, when I start the program from the terminal I get the following error message:  masterpdfeditor4: error while loading shared libraries: libsane.so.1: cannot open shared object file: No such file or directory   Does anybody know how to resolve this issue? I already executed  sudo apt install libqt5printsupport5 sudo apt install qt5-default sudo apt install --reinstall libqt4-svg libqt4-script libqt4-scripttools libqt4-sql libqt4-test   as suggested in other forums, but still the same error message appears.

Simple enough question: is there some shell command (or GUI method) I can use that, given the path to a file on my system, tells me what package put it there? Assuming the file did in fact come from a package, that is.  Bonus question: what if it's a file that isn't installed on my system? Is there, say, a website that will let me look up a file and see what packages, if any, provide it?


I need to prove a limit on a closed interval $[0,1]$.   $f$ is integrable.  $$\lim_{n\to \infty}\int_0^1 x^n f(x) \, dx=0$$  Where should I start from?

Suppose $f$ is a Riemann integrable function on $[0,1]$. Prove that $\lim_{n\to\infty} \int_0^1x^nf(x)dx=0.$   This is what I am thinking: Fix $n$. Then by Jensen's Inequality we have $$0\leq\left(\int_0^1x^nf(x)dx\right)^2 \leq \left(\int_0^1x^{2n}dx\right)\left(\int_0^1f^2(x)dx\right)=\left(\frac{1}{2n+1}\right)\left(\int_0^1f^2(x)dx\right).$$Thus, if $n\to\infty$ then $$0\leq \lim_{n\to \infty}\left(\int_0^1x^nf(x)dx\right)^2 \leq 0$$ and hence we get what we want. How correct (or incorrect) is this?


What does the gradient, the intercepts represent, what is the equation of my line, and how do I use this information to calculate emf?

If I have a plot of current ($y$ axis) against 1/Resistance ($x$ axis).  The circuit it is measured from is a simply 2 resistors connected in parallel to battery, where the potential across the resistors is $1V$. One resistor remains fixed, and the second varies, the resistance plotted on the graph is only the resistance of the second resistor.   Does this mean that the gradient will be voltage, but will it be $1V$ or less, as the resistance on the graph is only one from one of the resistors?  Also what will the $y$ intercept signify? $I = V/R +c$, what does the $c$ represent?


The question is :  Let $G$ be a finite group whose order is not divisible by $3$.Suppose that $(ab)^{3} = a^{3} b^{3}$ for all $a,\ b \in G$. Prove that $G$ must be abelian.  By the given condition it can be deduced that $(ba)^{2} = a^{2} b^{2}$ for all $a,\ b \in G$.But now how can proceed? Actually I think I have failed to do it because I have failed to use the condition that order of $G$ is not divisible by $3$. Please help me.  Thank you in advance.

As the title suggests. Let $G$ be a group, and suppose the function $\phi: G \to G$ with $\phi(g)=g^3$ for $g \in G$ is a homomorphism. Show that if $3 \nmid |G|$, $G$ must be abelian.  By considering $\ker(\phi)$ and Lagrange's Theorem, we have $\phi$ must be an isomorphism (right?), but I'm not really sure where to go after that.  This is a problem from Alperin and Bell, and it is not for homework.


I know that the question "how to correctly store Database credentials?" has been asked a lot, but in a discussion with a coworker that question resurfaced and we couldn't determine what was the correct answer:  Ini File:   Storing credentials in a .ini file looks elegant, but that kind of file can be viewed in a browser.   Php file:   In-script storage looks a little hardcoded but a hacker has to get into the server in order to peek at the file.   So what would be the best approach?  P.S.: Any other storage options are accepted  Thanks in advance

When a PHP application makes a database connection it of course generally needs to pass a login and password. If I'm using a single, minimum-permission login for my application, then the PHP needs to know that login and password somewhere. What is the best way to secure that password? It seems like just writing it in the PHP code isn't a good idea.


I recently received a new computer that I would like to dual boot both Windows 10 and some flavor of Linux on. I am planning on creating a separate partition for Windows and a separate partition for Linux "/".  However, I would like to create a data partition that would be accessible by both. Ideally, this partition would also keep "/var" and "/home".  Is there a particular FS type that would be ideal for use like this?  I understand that there is a similar question on here recommending either ext3 or NTFS, but the answers are from 2010 so I'm pretty sure the state-of-the-art has changed since then.   (from 2010)

Note: TL;DR, scroll to bottom for summary. I recently set up my computer for a dual boot between Ubuntu 9.10 and Windows 7. My current drive setup is as follows.  | A1 |     A2       | | B1    |  B2  | B3 |        A1: 100 mb, windows 7 "System   Reserved" boot partition      A2: 230 gb, data section, this one   needs to be shared between the   operating systems      B1: 125 gb, windows 7 OS      B2: 123 gb, ubuntu OS      B3: 2gb, linux swap space     Pretty much I want to have my documents, music, pictures, videos, etc accessible from both operating systems. My first attempt involved making the data (a2) partition NTFS, and moving my home folder from ubuntu to the data partition. However, as I read NTFS does not work nice with permission, and it messed up my home folder. My next idea is one of the following: 1) format the data partition to ext2/3/4 and move my home folder from linux there, and get a driver to read ext partitions in windows 7. The problem with that is that most of the ext drivers/software are not compatible with windows 7 or do not integrate with windows explorer (I really don't want to open a separate software window just to access my data, plus it's probably not compatible with other software.)  looks promising, but I'm not sure how it works with ext4 and windows 7 (not officially supported, when trying in Vista Compatibility Mode, it tells me I need to format the ext drive to use it). My next idea, 2) keep the home folder in ubuntu where it is, but create symlinks for the Documents, Music, etc folders to an NTFS formatted Data (A2) partition, and add those locations to the windows 7 libraries. I'm not totally sure how the permissions would work out, but it should be fine since it's only the documents, music, etc and not the important config files in the rest of /home/user/. Correct me if I'm wrong. Currently, symlinks is my best idea, although i'm not sure how it will work.  Any suggestions, additions to my ideas, links, pointers, whatever would be greatly appreciated. Even if it means I should reformat both my drives and repartition (2 250gb drives if you want to suggest a setup for that), I won't be too opposed if that's the best suggestion (I've gone through the format/install/format/reinstall process 5 times over the past 3 days, once more won't hurt me).    TL;DR, summary:  I have two hard drives. One is partitioned for Ubuntu and Windows 7, the second one I want accessible to both operating systems to store documents, music, pictures, videos, etc. Suggestions on how to set up the data drive.    P.S. bonus if I can get an apache server document root folder working between the two OS's as well (permissions could become very complicated, so don't worry too much about that)  P.P.S. Related question, but data viewing is one way:


Let's say I have a list of dictionnaries call x. If I want to extract the keys and push them into a new list called y :  y = {k for d in x for k in d.keys()} y = {k for k in chain(*x)}   Now I want to do the same operation with a function. As I don't know the name of the list of dict in advance, I was thinking of using *args  def formatting(*args):         return {k for d in args for k in d.keys()}  x_list = formatting(x)   But doing this return AttributeError: 'list' object has no attribute 'keys'  When I passing the real variable name in the function, it's working...  What is the correct way of passing list of dict into a function ?

In the following method definitions, what does the * and ** do for param2?  def foo(param1, *param2): def bar(param1, **param2):


What is the unary-& doing here?   int * a = 1990;  int result = &5[a];    If you were to print result you would get the value 2010.  You have to compile it with -fpermissive or it will stop due to errors.

As Joel points out in , in  (aka: K & R), there is mention of this property of arrays in C: a[5] == 5[a]  Joel says that it's because of pointer arithmetic but I still don't understand. Why does a[5] == 5[a]?


i am trying to make force download of mp3 file instead of open in browser.  i am using the following code.  header('Content-Disposition: attachment; filename="' . $name . '"'); readfile($path); exit();   This works fine, But the problem is resume/pause is not work and the total filesize/percentage is not mentioned when download the file. May i know how to fix this.

We are using a PHP scripting for tunnelling file downloads, since we don't want to expose the absolute path of downloadable file:  header("Content-Type: $ctype"); header("Content-Length: " . filesize($file)); header("Content-Disposition: attachment; filename=\"$fileName\""); readfile($file);   Unfortunately we noticed that downloads passed through this script can't be resumed by the end user.   Is there any way to support resumable downloads with such a PHP-based solution?


So I have recently been working with objects made with photogrammetry that I need to UV Unwrap. For that, I want to mark the seams of course but I find it very hard to select the lines I want to mark as seams because the mesh is triangulated. If I could just select two vertices and then the shotest way between those points that would be super useful. If not then what other methods would you suggest to UV unwrapping such a mesh?

I have been using Blender for quite a long time and I just want to make sure that there isn't a better way of selecting edges, that I might not be aware of. It is so cumbersome to have to click every single edge when I don't want to select an entire edge loop but a portion of one instead. I was wondering if there is some way in to specify a start edge and an end edge and then be able to auto select every edge in between?


\documentclass[11pt]{beamer} \usepackage[utf8]{inputenc} \usepackage[T1]{fontenc} \usepackage{lmodern} \usepackage{enumitem}  \usetheme{default}  \begin{document}  \begin{frame}     \frametitle{Tactics used for career advancement}     \begin{enumerate}         \item Consistently exceed performance expectations     \end{enumerate}  \end{frame}  \end{document}      TeX capacity exceeded, sorry [input stack size=5000]. \end{frame}   Removing the enumitem package fixes the problem, but in the real life I need that package to remove the left margin. In the real document I use: \begin{enumerate}[leftmargin=0cm]

The output in the MWE posted at the end of this post is shown below. Notice how the default indentation from itemize gives an asymmetric slide w.r.t the spacing to the left and right of the itemize environment. How can I push the bullet points to the left so that the spaces to the left and right are the same? Such a solution would ideally be:   implementable on a one-off basis, so that it is applied when necessary (since some itemize environments should be given the default indentation) independent of the margin size, so that the solution doesn't need to be changed when the margin size is changed     \documentclass{beamer}   \begin{document}  \begin{frame}{A title} \begin{itemize} \item Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod \item tempor incididunt ut labore et dolore magna aliqua. \item Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi \item ut aliquip ex ea commodo consequat. \begin{itemize} \item Duis aute irure dolor in reprehenderit in voluptate velit esse \item cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat \end{itemize} \end{itemize}    \end{frame} \end{document}


I'm using  sudo nano crontab -e   and this is in the map:  0 * * * * /companyname/fetch-schema.sh  @reboot sudo python /companyname/ups-shutdown.py   So it should run /companyname/fetch-schema.sh every hour but its not working.  The error i get when i use @reboot /companyname/fetch-schema.sh > /companyname/fetch-schema.sh is permission denied.  and chmod +x /companyname/fetch-schema.sh - chmod 755 /companyname/fetch-schema.sh are not working

I want to schedule a task to run on a regular basis and have heard that Cron is the way to do this.  How do I add Cron jobs in Ubuntu?


I have a query that will output something like this:  1 | 1 | Project A 2 | 0 | Project B   And I would like to obtain this:  1 | Yes | Project A 2 | No  | Project B   So, 1 must be converted to Yes and 0 to No. How can I do that directly in the query?  SELECT      project.id,     project.status,     project.name FROM     project

How do I perform an IF...THEN in an SQL SELECT statement?  For example:  SELECT IF(Obsolete = 'N' OR InStock = 'Y' ? 1 : 0) AS Saleable, * FROM Product


Take the following sentence I found myself typing in an email today:     Thanks for the update, Mark, good to hear.   That first comma had me hesitating for an embarrassing length of time. Consider the alternative:     Thanks for the update Mark, good to hear.   Honestly both look strange to me now that I'm overthinking it. Is there a rule I can defer to so I can make this easy and stop thinking about it?

According to some grammars[1][2] and CMS...  "Interjections and vocative should be separated from the rest of the sentence by commas".  The vocative case [1] is used to indicate direct address (i.e., to show when you are talking to somebody or something directly). Nouns in the vocative case are set off using commas. CMS 6.38  As direct address (i.e. vocative case), the parenthetical element should be set off using commas (CMS 6.30). An absolute phrase is always treated as a parenthetical element, as is an interjection.  So,      Hello, world!   That is a very classical way to hello the world.  But, languages change. I am not sure, but today, I feel that it is very uncommon helloing someone with an interjection, providing a small pause and clarifying who is helloed. I have an impression that usually people use hello as a ("kind of") verb, not an interjection.   Question: Is that just a personal (bad) impression or some linguistic has already studied that phenomenon?     [1] - Nelson, Gerald C., Director Survey of English Usage Sidney Greenbaum, and Sidney Greenbaum. An Introduction to English Grammar. Routledge, 2013. [2] - Advanced Grammar in Use with Answers: A Self-Study Reference and Practice Book for Advanced Learners of English. 3 edition. Cambridge University Press, 2013. CMS - Chicago Manual of Style


the file file contains these lines: hello world how are you  then I run the command head -n -1 file > file, expecting the last line to be deleted and the file updating to: hello world how are  but instead, the file ends up empty. Why does this happen?

I was trying to quickly edit an .hgignore file from the Cygwin bash shell today, and I added a line that was a mistake. I'm not sure if this was the best way to do it, but I quickly thought of using head -1 .hgignore to remove the offending line (I had previously only had one line in the file). Sure enough, when executed it gives the first line as the only output.  But when I tried to redirect the output and rewrite the file using head -1 .hgignore > .hgignore, the file was empty. Why does this happen? If I try appending instead, head -1 .hgignore >> .hgignore, it appends correctly but this is obviously not the desired result. Why does a truncating redirect not work in this case?


The straightforward null hypothesis for the Mann-Whitney U test is that the two distributions are identical. However, many documents (including ) also indicate that it is equivalent for comparing the medians of two distributions.  Suppose that two distributions have the same shape, when the null hypothesis is violated, some shift in location exists between the two distributions. My question is that when there is a shift in location, not only median but also mean (and other distribution properties) are different between the two distributions. Why do we specifically say it is a test for median? Is it possible that when the null hypothesis is wrong, and still the means of the two distribution are the same?

I've received a results from a Mann-Whitney rank test that I don't understand.  The median of the 2 populations is identical (6.9). The uppper and lower quantiles of each population are:   6.64 & 7.2 6.60 & 7.1   The p-value resulting from the test comparing these populations is 0.007. How can these populations be significantly different? Is it due to the spread about the median? A boxplot comparing the 2 shows that the second one has far more outliers than the first. Thanks for any suggestions.


Determine the equations of the tangent lines to the graph of $f(x)=3x(5x^2+1)$ that are parallel to the line $y=8x+9.$  I really don't know how to do this question; please help me out.

Find the equations of the tangent line(s) to $\;f(x) = x^3 -4x^2 + 2\;$ that are parallel to the line $y= -4x +3$.  I know the slope is -4 and $f'(x)= 3x^2-8x.$


Write question. Scroll down to bottom of page. Click "Review your question" button. Page scrolls to top and tells me my question is ready to publish. I now have to manually scroll back down to the bottom of the page to click the button now captioned "Post your question" to actually post the question.  Is this a big thing? No, and that's why it's so incredibly annoying, and so amazing that it wasn't detected and corrected when testing the new question experience. It's terrible UX, that's for sure. If my question doesn't need to be fixed before publication, please leave my window scroll position alone so I can click the button to actually post the thing.

This is terrible . I understand that the motivation behind "Review your question" is quality control, but if there is nothing for me to review, why can't the question be submitted in a single click?  Instead the page jumps back, to draw my attention to possibly this:    But it doesn't stand out in the UI, and if you didn't read that the button said "Review your question", it's hard to see why the page just jarringly jumped back instead of posting the question.  Is it really important for me to know that the automated system didn't find any way to improve my question?  Does Stack Exchange have metrics to see how often the question passes the quality check in the first go?  To add a minor point, as a veteran Stack Exchange user, the system doesn't have any reviews most of the time (in fact, the only time it had one is today while posting this question where it reminded me that one of feature-request, bug, .. tags were required).


Why "People" use "are" but "Everything" use "is" ?

Which is correct?     Everyone were convinced that he would go to the game.   Everyone was convinced that he would go to the game.   I think it's "was", because "everyone" is singular, but I just wanted to check.


Suppose my class hierarchy is as following class Company{ ...  }  class Employee extends Company{ ... }   class Interns extends Company{ ... }  class Test{         private List<Employee> employees;    private List<Intern> intern;     // Suppose that multiple objects of Interns and Employees have  been properly initialized and added to the above two Lists accordingly     public void process(List<Company> company){    ...    }     }  For my process(), I want to be able to use the same function without the need to overload (this is merely an example, I would have more classes, so overloading might seem to be very long). What should I do so that to the two Lists, so that they can be passed into process()? I have tried passing them directly. However, apparently, Java cannot cast List<Employee> or List<Intern> directly to List<Company> Also, is it better to write multiple overload methods (despite the amount) or try to cast the type so one function will take all.

I have a couple of questions about generic wildcards in Java:   What is the difference between List<? extends T> and List<? super T>? What is a bounded wildcard and what is an unbounded wildcard?


I realize that arr[::-1] returns a reversed view for arr. Further arr[st_index:end_index:increment] is a compact syntax for indexing while creating view. (BTW what is this way of indexing called?) So if I have code like: arr = np.array(range(10)) print(arr)  #prints: [0 1 2 3 4 5 6 7 8 9]  Now, if I want to see the arr as reversed I can try (I don’t need to subtract 1 from len(arr)): arr[len(arr)-1: 0: -1] #This gives o/p as: array([9, 8, 7, 6, 5, 4, 3, 2, 1])  The first element was not selected, which was expected. And if I change 0 to -1, i.e, if I try: arr[len(arr)-1: -1: -1] OR even arr[:-1:-1], I get an empty array. Apparently I get the reversed array view by: arr[::-1] Q: How is this working? If I do not specify the first two arguments how does it infer that it needs to continue till 0? In fact it is just interpreting that it needs to go till the boundary as arr[::1] gives normal array. Is this just coded as a special case or is there something more going on? And is there a way to get reversed array view by explicitly specifying the three expressions in indexing. i.e., are there any values for expr1, expr2, expr3 which can reverse arr in arr[expr1:expr2:expr3]?

I need a good explanation (references are a plus) on Python's slice notation.   To me, this notation needs a bit of picking up.   It looks extremely powerful, but I haven't quite got my head around it.


How do we find the sum of this series $$ \sum_{i=n}^m \binom{i}{r} $$ where,   $r<n<m$

After reading , the most popular answer use the identity $$\sum_{t=0}^n \binom{t}{k} = \binom{n+1}{k+1}.$$  What's the name of this identity? Is it the identity of the  modified.  How can we prove it? I tried by induction, but without success. Can we also prove it algebraically?  Thanks for your help.    EDIT 01 : This identity is known as the  because, on Pascal's triangle, when the addends represented in the summation and the sum itself are highlighted, a hockey-stick shape is revealed.


Let $L$ be a Lie algebra and $A$ be its subalgebra. Let consider $h : A \to Der(L)$ defined by $h(a)(l)=[l,a]$ then how to show that $h$ is Lie algebra homomorphism?  According to the definition of Lie algebras homomorphisms $h$ must satisfies  $ h([a_1,a_2])=[h(a_1),h(a_2)]$. Using Jacobi identity, we need to prove that $[[l_1,l_2]a]$  equals to $[[l_1,a],[l_2,a]]$ ? I have problem with calculation of Jacobi identity!  Edit: There are useful answers to this question: Checking a Lie homomorphism has been described carefully in  and .

The Jacobi identity of a Lie algebra says that $ad: \mathfrak g \to End(\mathfrak g)$ is a derivation. I am a bit emberassed but what is the easieast way to see that for every $X \in \mathfrak g$, $ad_X: \mathfrak g \to \mathfrak g, Y \mapsto [X,Y]$ is a Lie homomorphism, i.e., $[ad_X Y, ad_X Z] = ad_X([Y,Z])$ ?  Edit: The identity in the above line is wrong. It is $ad_X$ a derivation (endomorphism satisfying the product rule), not a Lie homomorphism (respecting the Lie bracket). I was a bit confused here, sorry.


In Harry Potter, wizards can use any magic they know at any time, regardless of how many wizards there are, how tired they are, how long they've been casting spells or how much magic is used around them.   We have huge battles like the Battle of Hogwarts in DH, where hundreds of magic users are concentrated in a few square km and use massive amounts of spells. We have battles that last hours and where the combatants are doing lots of running, casting and talking, like the Battle in the Ministry of Magic in OotP. Magical abilities also don't seem to be negatively affected by general health or age. Dumbledore, who is well over 100 years old, is able to duel Voldemort to a standstill. Harry could keep up the Priori Incantatem spell in GoF for a long time, even after doing the 3rd Triwizard Cup challenge, taking a Portkey over a long distance, being tortured by Voldemort and all the other stress accompanied by that.   When I look at other fictional works involving magic, they all seem to have a limit of sorts. In The Dresden Files, magic requires preparation, both in making sure you have enough of it and having certain material parts ready, like protective circles, special reagents or even jewelry to act as a focus for the magic, and using magic tires you out. In many versions of D&D, casters are limited by how many spells they prepared. A huge number of videogames use mana to limit casters. Just about any fantasy series I've consumed involving magic has limits on how much magic can be used by a single person, either by making the user get tired from using too much, by making the amount of magic in a certain location limited, or by coupling it to preparations or emotions.  Has J.K. Rowling or anyone else who worked on Harry Potter related content stated whether there are any physical limits to how much magic a single Wizard can use in a certain timespan?

Often in fantasies involving magic casting spells requires a certain physical or mental toll on the caster. I don't recall any mention of spells being physically or mentally taxing in the Harry Potter universe.  Does this mean they can cast an unlimited number of spells in a given day without any negative effect to themselves?


I am traying to make a mirror modifier popup, and i'ts working for the most part, but is saving the ''previous operations'' When i call it the first time it works as intended, i can choose the axis that it will mirror, but after if i call it again and press any button it will apply all the settings i have choosen previously. Can i reset it everytime or something?. Also, isn't there any better way to make modifiers popup instead of having to make all of it manually?  class DC_MT_popup_mirror(bpy.types.Operator):     bl_idname = "popup.dc_mirror"     bl_label = "Mirror Popup"     bl_space_type = "VIEW_3D"           def execute(self, context):        pass               def invoke(self, context, event):         wm = context.window_manager                return wm.invoke_popup(self, width=100)         return {'FINISHED'}                 def draw(self, context):         layout = self.layout         row = layout.row()                  layout.label(text="Mirror")                                row = layout.row()         row.operator('3dview.dc_mirror', text= "X").x_axis = True         row.operator('3dview.dc_mirror', text= "Y").y_axis = True         row.operator('3dview.dc_mirror', text= "Z").z_axis = True                       return {'FINISHED'}           class DC_OT_mirror_add(bpy.types.Operator):     bl_idname = '3dview.dc_mirror'     bl_label = 'Mirror Axis'              x_axis : bpy.props.BoolProperty(name = "X Axis", default = False)     y_axis : bpy.props.BoolProperty(name = "Y Axis", default = False)     z_axis : bpy.props.BoolProperty(name = "Z Axis", default = False)               #pos_axis :bpy.props.IntProperty(name = "X Axis", default = -1)          def execute(self, context):         ob = context.object         #x = x_axis                                                 if "dcMirror" not in ob.modifiers:             ob.modifiers.new(name="dcMirror", type='MIRROR')             ob.modifiers["dcMirror"].show_on_cage = True             ob.modifiers["dcMirror"].use_axis[0] = False             ob.modifiers["dcMirror"].use_clip = True                              if self.x_axis:             ob.modifiers["dcMirror"].use_axis[0] = self.x_axis             ob.modifiers["dcMirror"].use_bisect_axis[0] = self.x_axis                                           if self.y_axis:               ob.modifiers["dcMirror"].use_axis[1] = self.y_axis             ob.modifiers["dcMirror"].use_bisect_axis[1] = self.y_axis             ob.modifiers["dcMirror"].use_bisect_flip_axis[1] = self.y_axis                      if self.z_axis:               ob.modifiers["dcMirror"].use_axis[2] = self.z_axis             ob.modifiers["dcMirror"].use_bisect_axis[2] = self.z_axis                                          return {'FINISHED'}                       classes = (     DC_MT_popup_mirror,     DC_OT_mirror_add,    ) register, unregister = bpy.utils.register_classes_factory(classes)    if __name__ == "__main__":     register()```

I'm writing an operator for which it is crucial that every time it gets called all the properties are set to their default values.   The ops.object.delete has 1 param. use_global. It is always false, no matter what the user put in last time it got called. I would like to replicate exactly that.   (For example: I want to modify delta scale. The default val for my_factor is 1, so nothing happens until the user alters that number. If the user calls the operator again, it will have stored whatever number the user has used last, however I want it to always start with 1.)


I would like to install android 2.3 or 2.2 in my Samsung Omnia 2.  Could you tell me how should I do?

Many people want to try/use Android without buying a new Android phone.  How can I install Android on my current phone or device running Nokia Symbian, Maemo, or MeeGo; Microsoft Windows Mobile or Windows Phone 7/8/10; Apple iOS (iPhone); RIM's BlackBerry OS; Palm's WebOS; Samsung's Bada; HP's WebOS; Mozilla's Firefox OS; or other phone / operating system?


Let f be a continous function in the section $[0,1]$. $f(x)>x \ \ \forall x\in[0,1]$. Prove that $\exists\epsilon>0 \ s.t \ f(x)>x+\epsilon :\ \forall x\in[0,1]$  From $f(x)>x$ I know that f is monotone increasing. So $\forall \delta>0 \ |x-y|<\delta$ and $\forall \epsilon>0 \ |f(x)-f(y)|<\epsilon$. Though I have a feeling that this doesn't involve delta. How should I continue from here ? Maybe this have something to do with intermediate value theorem ?

Let $f$ a continous function defined in the interval $[0,1]$. Assuming: $\forall x \in [0,1]:f(x) > x$ Prove: $\forall x \in [0,1]:f(x) > x + \varepsilon $  I tried to use  and did some Algebra tricks but it didn't bring me to a safe shore :)    What do you suggest? Thanks!


I have directory structures like below..     |---- folder1         |---- __init__.py         |---- python_file1.py    |---- folder2         |---- __init__.py         |---- python_file2.py   while i try to import like this "folder2.python_file2 import some_function".  it give an error: ImportError: cannot import name some_function  and also i had look many answer in stack overflow they said to insert file path if the directory without __init__.py file. But even i have __init__.py I cant able to import function from that directory. Let me clear about this error.  Thanks.

Imagine this directory structure:  app/    __init__.py    sub1/       __init__.py       mod1.py    sub2/       __init__.py       mod2.py   I'm coding mod1, and I need to import something from mod2. How should I do it?    I tried from ..sub2 import mod2 but I'm getting an "Attempted relative import in non-package".  I googled around but found only "sys.path manipulation" hacks. Isn't there a clean way?      Edit: all my __init__.py's are currently empty    Edit2: I'm trying to do this because sub2 contains classes that are shared across sub packages (sub1, subX, etc.).  Edit3: The behaviour I'm looking for is the same as described in  (thanks John B)


I recently edited  on MA stack exchange, and within 10 minutes posted an answer. My answer received 2 votes.  When I look at my badges, the "explainer" badge has not yet been conquered. Now, this is where it get's strange:   Notice that I have 1/500 for "Illuminator", which means that I should have gotten the "explainer" badge already. Is this a bug? Am I missing something?

I recently , but didn't receive an explainer badge. I found a couple of questions from people who appeared to have the same problem as I do, but in the end it turned out they just didn't meet all the conditions for the badge.   The time between my edit and my answer was 1-2 hours. Following all the bullet points for an explainer badge from :        The question was asked by someone other than the answerer      Yes, I didn't ask the question        Neither the questions nor the answers are deleted      Also true        The questions are not closed      The question is open        The answers score > 0      I have a score of 1        The question edits changed either body, titles, or both      I edited both the title and body (I also added two tags, but that shouldn't be an issue..)  Any ideas why I didn't get my badge? Am I just too impatient?


Regarding time, years, which of these two words — last or past— should be used to state tense of time passed?     Sister Esther and her family have been members of our church for the last/past seven years.   In this particular sentence which word would work best? And what would their respective meanings convey?

Is it grammatically  wrong  to say      It's been too hot  in the last / the past few days      It's been too hot for the last / the past few days     I saw this following sentence also, can we omit in it?     He's had two new cars in the last / in the past three years   as     He's had two new cars  the last / in the past three years     Is there a strict rule in using of preposition or non-preposition when we use the last/past ?  What is the structure when I refer to weeks, months ?


When you mount a drive or have Google account integration with "Files" application on in Ubuntu 19.10, an icon appears in the dock.   How do I change this behavior? I don't want any of these icons to show up on the dock.

I just upgraded from Ubuntu 19.04 to Ubuntu 19.10. This made that my second internal HDD show up in the launcher bar or Ubuntu Dock, which it did not before.  I read that I should mount it to /mnt instead of /media, but this device was auto-mounted years ago (I believe in Ubuntu 16.04 or so) and I have a lot of symlinks and other references to the path in /media already.  How can I remove the icon from the dock without unmounting it or having to mount it to a different location? I can not even move it to another location on the bar.


Let's say that I have one categorical variable with six levels, and I then create five indicator variables in order to represent the six levels. If two of the five variables are insignificant, then do I drop these two? I assume not, but I was not sure. I was thinking that it might be better to test the full (all five variables) versus the reduced (just the three significant variables)  model and, if that was not significant, then just leave all five of the variables in. I was not sure what to do. Oh and I meant for this to be in the context of fitting a logistic regression model.

After seeking clarification about linear model coefficients  I have a follow up question concerning non-signficant (high p value) for coefficients of factor levels.  Example: If my linear model includes a factor with 10 levels, and only 3 of those levels have significant p values associated with them, when using the model to predict Y can I choose to not include the coefficient term if the subject falls in one of the non-signficant level?  More drastically, would it be wrong to lump the 7 non-significant levels into one level and re-analyze?


$$\sqrt{1+\sqrt{2+\sqrt{3+\ldots}}}$$  My approach    1st approach:  Let $\sqrt{1+\sqrt{2+a}} = x$, where $a$ is a result of the lower portion of the continued nested radical and $1+\sqrt{2+a}$ is a perfect square, and $x$ is a number that doesn't contain a radical.   Solving for $a$ gives 7, and $x$ equals to 2.  2nd approach:  Using a software, $\sqrt{1+\sqrt{2+\sqrt{3+\ldots}}} \approx 1.75793...$  What is the best approach for the nested radicals?

I would like to investigate the convergence of  $$\sqrt{1+\sqrt{2+\sqrt{3+\sqrt{4+\sqrt\ldots}}}}$$  Or more precisely, let $$\begin{align} a_1 & = \sqrt 1\\ a_2 & = \sqrt{1+\sqrt2}\\ a_3 & = \sqrt{1+\sqrt{2+\sqrt 3}}\\ a_4 & = \sqrt{1+\sqrt{2+\sqrt{3+\sqrt 4}}}\\ &\vdots \end{align}$$  Easy computer calculations suggest that this sequence converges rapidly to the value 1.75793275661800453265, so I handed this number to the all-seeing Google, which produced:       Henceforth let us write  $\sqrt{r_1 + \sqrt{r_2 + \sqrt{\cdots + \sqrt{r_n}}}}$ as $[r_1, r_2, \ldots r_n]$ for short, in the manner of continued fractions.  Obviously we have $$a_n= [1,2,\ldots n] \le \underbrace{[n, n,\ldots, n]}_n$$   but as the right-hand side grows without bound (It's $O(\sqrt n)$) this is unhelpful.  I thought maybe to do something like:  $$a_{n^2}\le [1, \underbrace{4, 4, 4}_3, \underbrace{9, 9, 9, 9, 9}_5, \ldots, \underbrace{n^2,n^2,\ldots,n^2}_{2n-1}] $$  but I haven't been able to make it work.     I would like a proof that the limit $$\lim_{n\to\infty} a_n$$   exists. The methods I know are not getting me anywhere.   I originally planned to ask "and what the limit is", but OEIS says "No closed-form expression is known for this constant".  The references it cites are unavailable to me at present.


I have a dict as in below:   saving = {0: (1, 2, 9.0), 1: (1, 3, 603.0), 2: (1, 4, 396.0), 3: (1, 5, 9.0), 4: (2, 3,     206.0)}    I want to sort descending this dict order by the third value. I tried sorted and sort() but I couldn't sort the dict. I don't know much about the usage sort and sorted functions.  Can you help me ?  Thanks.

I have a dictionary of values read from two fields in a database: a string field and a numeric field. The string field is unique, so that is the key of the dictionary.  I can sort on the keys, but how can I sort based on the values?  Note: I have read Stack Overflow question here  and probably could change my code to have a list of dictionaries, but since I do not really need a list of dictionaries I wanted to know if there is a simpler solution to sort either in ascending or descending order.


If   $$\sin x + \cos x +\tan x + \cot x +\sec x +\csc x=7$$   then show that $\sin(2x)$ is a root of the equation $x^2 -44x + 36$.   How do I solve this question?

$$ 0<\theta<\pi/2$$   and $$\sin\theta+\cos\theta+\tan\theta+\cot\theta+\sec\theta+\csc\theta=7$$   then show that $\sin 2\theta$ is a root of the equation $$x^2 -44x +36=0$$   I tried to use the above given equation of all the trigonometric ratios, though I ended up with an expression of $\sin\theta\cos\theta$.   But this too is in the form of $\sin\theta$ and $\cos\theta$ which was $\sin\theta\cos\theta=\frac{1}{6-\sin\theta-\cos\theta}$.  When I put that in the quadratic equation, it would again transform into the form of $\sin\theta$ and $\cos\theta$, and hence at last I couldn't prove the thing.  Even hints would work, as I would like to solve the question myself.


While reading a deleted post from Meta Stack Exchange at , I saw one of the older "protected question" labels:  And then I saw one of the newer protected labels (this is a screenshot from a screenshot):  I kind of preferred the older version of the protected question label, or the text at least.  Saying that the association bonus doesn't count for checks like that helped  for newer users (and some older ones too).  Removing that message causes confusion to some new users with the . Feature request:  Could we add that message back into the protected question labels, as it will be clearer and a bit more accurate?

The new notice for protected questions looks like this:     Earn 10 reputation in order to answer this question. The reputation requirement helps protect this question from spam and non-answer activity.  The phrasing of this notice leaves out a lot of info, and is incorrect in many cases:  In the case where the user has just created their account on the site (whether or not they have the association bonus of +100), the default 1 for signing up does count toward the required 10. The message implies that the user has to earn 10 more reputation for a total of 11 (or 111), while the actual requirement is 10 (or 110).  If the user just registered and started off with the association bonus, then later lost part of it (e.g. through bounties or making a downvoted post), earning 10 reputation is not enough to answer protected questions. According to the literal wording of the notice, earning 10 reputation is enough regardless of previous rep loss, but this is not the case.   The easiest fix that can be made, to at least fix part of the problem, would be to explicitly indicate that the association bonus does not count. This was implemented in the prior protected question notice in response to , but was omitted from the new notice. This omission  , and adding this back would remove that. Can we please fix this notice?


Gaining reputation from answering on Stack Overflow is getting increasingly difficult. There are many talented users to answer most questions within minutes, providing good enough answers immediately and editing in fuller answers within a very short time. Sometimes I feel like gaining reputation is somewhat of a race. However, I mean this in a good sense - it's a fun race, and it's great to have answers to most questions supplied most quickly.  But it saddens me to see how easily reputation can be gained by just asking questions. I know this has been discussed here on Meta Stack Overflow several times, but I want to highlight a pattern. Take a look at the  (I tend to scan through this list on weekends). I don't want to point fingers, but many questions there have already been asked multiple times before. Stack Overflow veterans surely scan with their eyes, nodding - been there - over most of them. And yet, these questions gain lots of reputation. Some get closed in a couple of hours, but still manage to gain many votes until then.  This isn't a good situation, IMHO. Many members on Stack Overflow brandish high reputations and when you enter their profile it's a few 100s of questions, 3 downvoted answers on some  semi-subjective topic, and nothing more. Is this the 4K user employers would like to hire based on high Stack Overflow reputation?  Perhaps to prove this, it's worthwhile to make an experiment - a user that asks semi-subjective questions over and over again, on topics which haven't been discussed in the past week or so. I have a feeling this can show some nice results, reputation-wise.  I know there are open issues on User Voice on this issue, but is someone planning to do anything about it? IMHO too much reputation is gained by asking questions, it is blatantly obvious, and it makes Stack Overflow a less fun place to be - as it partially invalidates the whole reputation system.    Why less fun? Consider this scenario:  Bob: So are you knowledgeable in    programming?  Alice: Yeah, I have a Stack Overflow reputation of 8K!  Bob: Eh, I knew people get to    such reputations just for asking hundreds of    repeating questions there. So that    doesn't count. Any other proof of    your expertness?  Sounds surreal? I disagree. As an employer interviewing people quite often, such a scenario is real for me. I just value Stack Overflow reputation less because of this, period. Stack Overflow's administrators have to decide what they want out of it. Is it just a website for getting your questions answered? Great - it's a great one, indeed. But it appears they want to make something more, connecting to Careers, meaning reputation to actually be real. In such a case, allowing reputation farming from repeated questions is a self-defeating strategy.

After thinking about    which I declined for the reasons , and    I have a proposal.  How about if question upvotes were only worth +5 rep instead of +10? And this was applied retroactively? (answer upvotes would be unchanged from the current behavior, so this would be question specific.)  This seems to be a better solution to the particular  problem  without all the rather serious negative repercussions of increasing the punitive value and/or cost of downvotes across the board.


Why this code compiles and returns 1?  int main(int ac, char* av[]) {     return ac[av] == 0; }

As Joel points out in , in  (aka: K & R), there is mention of this property of arrays in C: a[5] == 5[a]  Joel says that it's because of pointer arithmetic but I still don't understand. Why does a[5] == 5[a]?


I am trying to work out the following two integrals involving a standard Brownian motion started at $W_0 = 0$.  The first expression is bewildering me a bit, since it seems like somehow the Itô isometry is involved and would help me work the expectation. $$ \mathbb E\left[\left(\frac{1}{T}\int_0^T\,W_t\,dt \right)^2\right] $$ Secondly, it seems like to prove the following inequality it could be useful to reach an expression resulting in $\frac{2}{\sqrt{\pi}}$, but I am not sure how to do it. $$ \mathbb P\left(\int_0^1\,W_t\,dt > \frac{2}{\sqrt{3}} \right) $$  Any help is welcome!

For a standard one-dimensional Brownian motion $W(t)$, calculate:   $$E\bigg[\Big(\frac{1}{T}\int\limits_0^TW_t\, dt\Big)^2\bigg]$$  Note: I am not able to figure out how to approach this problem. All i can think of is that the term $\frac{1}{T}\int\limits_0^TW_t\,dt$ is like 'average'. But not sure how to proceed ahead. I'm relatively new to Brownian motion. I tried searching the forum for some hints..but could not find one. I will really appreciate if you could please guide me in the right direction. Thanks!


I am struggling to find $$\lim_{n\rightarrow\infty}n!^{1/n}$$  being trying this for ages, I know that:  $$\lim_{n\rightarrow\infty} n^{{1}/{n}} = 1$$  which might be useful for using pinching theorem. but I can't think of a way to 'trap' the function underneath.

I am trying to evaluate the $\lim(\sqrt[n]{n!})$ using 2 theorems (2 proofs)   Theorem 1: Let $\{c_n\}$ be any sequence in $\mathbb{R}^+$. Then, $\displaystyle \underline{\lim}\frac{c_{n+1}}{c_n}\leq \underline{\lim}\sqrt[n]{c_n}$ and $\displaystyle \overline{\lim}\sqrt[n]{c_n}\leq \overline{\lim}\frac{c_{n+1}}{c_n}$.    so with 1. I have $\frac{(n+1)!}{n!}$ =$n+1$  which is $\overline{\lim}=\infty$   and 2 with $\sqrt[n]{n!}\geq\sqrt[n]{(n/2)^{n/2}}$=$\sqrt{\frac{n}{2}}$ which is $\overline{\lim}=\infty$  is it valid?  P.S I was not using theorem 1 right


The loop I'm trying to run will initialize but will not continue to run after the first loop.  Since I know where the problem i took out most of the code to fix the loop.  After i make the second selection the loop will not run.  Thank you for any help.  public static void main(String[] args) {   String number; // enter number           int stringLength = 0;       String selection = "y" ;   // Create a Scanner object to read input.   Scanner keyboard = new Scanner(System.in);   // PrintWriter outputFile = new PrintWriter("outDataFile.txt");  // outputFile.close();    while (selection == "y")   {       // Get the user's number.      System.out.print("Write your number ");      number = keyboard.nextLine();        System.out.print("y/Y to continue, any else to exit");      selection = keyboard.nextLine();     }  }

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've got a string test_string like 'Hello, two is a number'" and I want to copy the characters between position 7 and 12. In the programming language I use:  test_string = 'Hello, two is a number' new_string = string_copy(test_string, 7, 12)   the value of new_string would be ' two i'. My example might be a bit stupid, but does a function exist in Python equal to string_copy?

I need a good explanation (references are a plus) on Python's slice notation.   To me, this notation needs a bit of picking up.   It looks extremely powerful, but I haven't quite got my head around it.


I selected Alternative and then Ubuntu 16.04.3 LTS desktop version. I planned on downloading the server version ( I thought I needed the both of them), but I stopped it after learning that only one of them was needed. Okay, the torrent download is completed, I opened the file, all I see  is a desktop image file ( and the server file for some reason as well), also the torrent file for the server. What do I do now?  Apologies, I'm new to this changing OS thing...

I would like to see a full how-to guide on how to install Ubuntu.


As new researcher and having started my PhD studies less than one month, I would like someone experienced to give me some advice.  As researcher, which are your habits concerning research papers you read. How you choose the literature you read ? Do you 'follow'  journals/ research groups/conferences/topic?  Are there tools for this reason?

When I started my Masters thesis one advice I got for getting good material to read was to subscribe to several journals' alerts system, so that I would get mails with eTOC (electronic Table of Contents).  This was pretty cool then, for months I could stay on top of what's been published out there and was up to date in my own little narrow area. Now almost 3 years later that list of journals have expanded a bit, and the more work I have at the lab more mails that accumulate in my mailbox. What used to be no more than 10 unread mails is now about 900. The output is more than I can handle, what more restrictive method can I implement?  I guess it is pretty clear that this way of following literature is not sustainable in the long run. So I wonder if there are other and perhaps better ways of staying on top of recently published articles?    Please note that I have checked the following two questions prior to asking this one. I do feel though my question differs from these two in its essence.


Evaluate:    $$\underline{\quad\int _0 ^\pi x^3 \ln (\sin x) \mathrm d x\quad\:}\\{\int _0 ^\pi x^2 \ln(\sqrt 2 \sin x) \mathrm d x}$$   I tried expressing the integral in the numerator as a multiple of the integral in the denominator. To do this, I used the following property of definite integrals:  \begin{align} \int _a^b f(x) \mathrm d x &= \int _a ^b f(a+b-x) \mathrm d x \\ &\Downarrow \\ 2 \int _a^b f(x) \mathrm d x &= \int _a^b f(x) \mathrm d x + \int _a ^b f(a+b-x) \mathrm d x \tag{1} \end{align}  Applying this property to the integral in the numerator, we get:  \begin{align} \int _0 ^\pi x^3 \ln (\sin x) \mathrm d x &= \frac 1 2 \int _0 ^\pi ((\pi-x)^3 + x^3) \ln (\sin x) \mathrm d x\\ &=\frac 1 2 \int _0 ^\pi (\pi ^3 -3\pi^2 x +3\pi x^2)\ln (\sin x) \mathrm d x \tag{2} \end{align}  Now if we apply property $(1)$ to the integral  $$\int _0 ^\pi x^2 \ln (\sin x) \mathrm d x$$  then we see that  $$\int _0 ^\pi x^2 \ln (\sin x) \mathrm d x = \int _0 ^\pi (\pi-x)^2 \ln (\sin x) \mathrm d x$$  Thus upon simplifying, we get  $$\frac{\pi}{2}\int _0 ^\pi \ln (\sin x) \mathrm d x= \int _0 ^\pi x \ln (\sin x) \mathrm d x \tag{3}$$  Now substituting this result in equation $(3)$, we get  $$\int _0 ^\pi x^3 \ln (\sin x) \mathrm d x =\frac 1 2 \int _0 ^\pi \left(3\pi x^2 - \frac{\pi^3}{2}\right) \ln (\sin x) \mathrm d x$$  Now I have reduced the integral in the numerator in two two terms, one ($x^2$ term) which is a multiple of the term in the denominator and other which isn't. And sadly, I am not able to go any further at simplifying it. So how do I express the integral in the numerator as a multiple of the integral in the denominator? Is this approach of converting to a multiple, the only approach? Can we directly compute the integrals and then take their ratio? I also realize that computing the exact value of both of the integrals and then taking their ratio will be cumbersome and would also involve applying a few limits as the givven integrals are improper integrals.    I am looking for answers which continue the solution from the point where I left and lead me to the final answer. And just in case if you need to know the answer, then it is:      $$\frac{3\pi}{2}$$

Calculate   $$\frac{\int_0^\pi x^3\ln(\sin x)\,dx}{\int_0^\pi x^2\ln(\sqrt{2}(\sin x))\,dx}$$   In this problem, I'm unable to understand how to start.  I tried applying integration by parts but I couldn't solve it. I also tried the various properties of definite integration but they were of no use. Maybe applying integration by parts (or DI method) successively may work but it leads to a form of $\frac{\infty}{\infty}$.


asked to make per-site metas more accessible, from which, updates were made to make the searching more clear, and allow a user to add them to their sites list.  This still requires manual user input however. Could a link to the per-site metas be added to the remarkably empty looking 'more' menu? I'd see it as fitting quite well alongside a link to your per-site profile.

The iOS app has no convenient way to get from a main site to its Meta. You have to go to the full site list and search for the specific Meta you want.  Could a link be provided somewhere? My first thought would be for a tap or tap-and-hold on the site name at the top of the Questions tab to pop up a "menu" with a link to the Meta (see the Taskpaper iOS app for this behavior). The Meta should likewise provide a link back to Main.


I am trying to learn C++, but I can't even make the first (hello world) example from cplusplus.org work with g++ command or c++. I created a file just like the example and ran g++ myfile, then ./myfile.  I get a permission problem, then I use chmod +x myfile and the permission problem is gone but this problem happens:  gzuspower@gzuspower:~/Desktop$ ./4 ./4: line 1: //myfirst: No such file or directory ./4: line 4: syntax error near unexpected token `(' ./4: line 4: `int main ()'   I called my file 4 because it is my 4th attempt. This is on Xubuntu 16.04.The duplicate question answer did not work i tried .c ,.cpp ,as file extension and tried firstc++ (my first attempt file) instead of 4(my fourth attempt file) and nothing works. i'm going to try different form of hello-world code.

I am  new to Linux. I am using Ubuntu 11.04 and do not know how to compile and execute C++ program in it. I need to know the commands to Compile and Execute a C++ program in Linux.


I am trying to solve the following problem in real analysis: Let $(a_{n})$ be a non-negative sequence in which $a_{n+m} \leq a_{n}a_{m} \; \forall n,m \in \mathbb{N}$.  Show that the sequence $(\sqrt[n]{a_{n}})$ converges and that $\displaystyle \lim_{n \to \infty}\sqrt[n]{a_{n}}=\inf\{\sqrt[n]{a_{n}}|n \in \mathbb{N}\}$.   So far, I have deduced from the assumption $\displaystyle a_{n+m} \leq a_{n}a_{m} \; \forall n,m \in \mathbb{N}$ that $\displaystyle a_{n} \leq a_{1}^{n} \; \forall n \in \mathbb{N}$. So $(a_{n})$ grows at most exponentially. Also, since $\displaystyle \sqrt[n]{a_{n}}=e^{\frac{\log(a_{n})}{n}}$, I'm trying to show that the sequence $\displaystyle \frac{\log(a_{n})}{n}$ either converges or diverges to $-\infty$ instead, but I haven't been able to do so.   Any help would be greatly appreciated. Thank you.

Let $a:\mathbb{N}\to\mathbb{R}^+$ be a sequence such that $a_{m+n}\leq a_ma_n$. Prove that $\sqrt[n]a_n$ converges and $$\lim_{n\to\infty}\sqrt[n]a_n=\inf_{n\in\mathbb{N}}\sqrt[n]a_n.$$  So far all I have is $\sqrt[n]a_n\leq a_1$ (from $a_{m+n}\leq a_ma_n$ by induction). If it is true that $\sqrt[n]a_n$ monotone decreasing, we are done but I couldn't show it. Should I do something with $\liminf$ and $\limsup$?


The very first thing we saw in 1977 at the beginning of a New Hope was "A long time ago, in a galaxy far, far away..." It tells us that Star Wars of course takes place in the past. How long ago in the past does it take place though? At what stage of development were we on Earth during the time that Star Wars takes place?  Moreover, do we even exist during the time of Star Wars? Is there any mention of how long ago in our time Star Wars took place?

Kind of brought to my attention by .  The poster mentions non-humans, which implies that there are humans in the Star Wars universe.  However, since it happened "A long time ago, in a galaxy far far away", how could there be any humans in the Star Wars universe?  Are there "humans" in Star Wars there just because it was easier to make the movies that way?  Other shows such as Star Trek are about the future of humans, so it's easy to understand the existence of humans in those storylines.  However for Star Wars it just doesn't make sense.  It also seems odd that they'd go around creating all these different species and then just leave the main characters as humans. I guess another possibility is that the humans in star Wars eventually populated Earth, but then what happened to all the technology?


I'm new at using beamer, and I would really appreciate your help. Preparing a presentation I've chosen the Goettingen theme, which places a sidebar showing the contents for each of the slides. I would like to remove it from the title page and the table of contents, so frames 1 and 2 would    show a different them with the same colourtheme, or  find a command to remove the sidebar from the selected frames.    This is mi minimal example,  \documentclass{beamer}  \mode<presentation> {   \usetheme{Goettingen}        \usecolortheme{beaver}    \usefonttheme{default}     \setbeamertemplate{navigation symbols}{}   \setbeamertemplate{caption}[numbered] }   \usepackage[spanish]{babel} \usepackage[utf8x]{inputenc}  \title[ShortTitle]{Fulltitle} \author{GV, R} \institute{University} \date{16 de Junio, 2014}  \begin{document}  \begin{frame}   \titlepage \end{frame}  \begin{frame}    \frametitle{Contents}   \framesubtitle{}   \tableofcontents  \end{frame}  ....  \end{document}

Edited for clarity:  I am trying to remove the navigation information in the sidebar that lists a TOC on the title page and the TOC page in a beamer presentation.  I still want the sidebar to appear for presentation background consistency, but I want it to be blank.  I'm using the PaloAlto theme.    I have found a work around for the title page by setting the background of the title page as a rectangle the size and colour of the sidebar on top of the sidebar by using \addtobeamertemplate{title page}, but this approach doesn't work for the TOC page as I can't find a way to link to that page specifically through the template definition.  Is there an easier way to hide the sidebar on only the title page and TOC page? Thanks!


I'm currently following a course in quantum mechanics that uses Griffith's textbook.  Griffiths shows that wave functions are members of a Hilbert space. Since this is an abstract vector space, we can assign a state vector $|{\psi}>$ to each wave function $\psi(x)$. Since our course on linear algebra runs pretty deep, this I understand.  Griffiths subsequently defines the inner product between two state vectors $<\phi|\psi> = \int\phi^*(x)\psi(x)dx$, and he derives all sorts of fun things from this inner product; that the function $\psi(x)$ corresponding to $|\psi>$ is the wave function as seen previously in wave mechanics, and that its Fourier transform determines the probability density of momentum.  At this point, something happens in both Griffiths and my course that I don't quite comprehend. Both my instructor and the book mention that at this point, the vectors will take precedence above the functions; all quantum mechanical information is from now on fully and completely recorded into the vector. The functions are simply a representation of this vector; one of the many possible representations. Am I correct in saying this?  But Griffith's proof that the coefficients in the position basis of $|\psi>$ form the values of the function $\psi(x)$ is completely based on the definition $<\phi|\psi> = \int\phi^*(x)\psi(x)dx$. How should I then read this? Does he assume that there is a function representation $\psi(x)$ corresponding to the state vector $|\psi>$ (which is in his right, since $L_2$ is isomorphic to the vector space), to subsequently derive the properties of this function?   To me it just seems really strange that we have these abstract state vectors, only to define the inner product in terms of one very specific representation of that vector.  Edit 6 February 2019: I can (for obvious reasons) not unmark this question as a duplicate, but I can "edit to explain why my question hasn't been answered before." My question is not about whether the ket psi and the wave function are the exact same--I have written in my question that I understand that the wave function is a representation of the ket (in other words, I've used the answer to the duplicate question to ask my own question). My question is why in so many derivations, it appears that the wave function formulation takes precedence (in e.g. the definition of the inner product). In the answers below, it has been explained that there is no precedence, and that this is simply a shortcut in the theory.

So I'm going through my notes and I think I've confused myself. We often imply  $$ |\psi\rangle \to \psi(x)\\ \langle\psi| \to \psi(x)^* $$ for instance when we talk about eigenvalue equations we interpret  $$ \hat{H}|\psi\rangle =E|\psi\rangle $$ as simply  $$ \hat{H}\psi(x)=E\psi(x) $$ but I don't understand why we say $|\psi\rangle \to \psi(x)$ because if that was the case then  $$ \langle\psi|\psi\rangle=|\psi|^2 $$ when clearly $$ \langle\psi|\psi\rangle=\int_{-\infty}^\infty |\psi|^2 dx = 1 $$ I'm obviously missing something simple, could anyone point out where I'm going wrong?


I want to provide my customers with a plugin which they can include in their website. Problem is that the content of the iframe changes everyday and has different heights. As I know the height of an iframe can be specified with css or a simple height tag, but then the height is fixed. I want to make the height change dynamically with the content, and this can be done with JavaScript, but how can I include a working JavaScript line inline the iframe code, so I don't confuse my customers?  Like  <iframe src="..." border="..." onload="..."></iframe>   EDIT I want to provide a single line of code, so that this code can be easily be implemented into the websites from my user.

I am working on an iGoogle-like application. Content from other applications (on other domains) is shown using iframes.   How do I resize the iframes to fit the height of the iframes' content?  I've tried to decipher the javascript Google uses but it's obfuscated, and searching the web has been fruitless so far.  Update: Please note that content is loaded from other domains, so the  applies.


What is the experimental evidence that suggests the existence of quarks? How were they discovered? I'm going to assume a particle collider is involved, as it tends to be the case with most subatomic discoveries these days.  How are we able to study something so small with any type of instrument? It seems like at some point, we wouldn't be able to build an instrument on the scale required to detect something so small.  (Would be nice if this could be explained in such a way that a College Physics 1 / 2 could understand it.)

In our current theories all hadrons are made up of quarks and gluons.  This view reduces considerably the big family of hadrons by providing a very logical structure in which all quantum properties values of the hadrons are originated from the valence quarks' quantum properties. But since they cannot be observed isolated, in the sense that electrons or positrons can be, the theory assumes color confinement is just part of the game.  However actual calculations of QCD use a view where they are quarks and gluons are distributed in a space-time volume, which is needed to describe much of the rich phenomena of high energy physics.  But all of this makes me wonder:   Are quarks real and elementary? I mean, is there more evidence supporting that they are more than just a model that works?  Since hadronic matter cannot by split into pieces smaller than the smallest hadron, couldn't reality be explained also by a model where all observable hadrons are the elementary ones, which follow rules for transforming into other ones, etc.?  By the way, this last idea was already presented by Hagedorn on his very famous known paper, in the end where he tries to give a phylosofical point of view to his model, so I wonder why was it discarded.


I've never done anything with APIs before so this question is going to be badly asked. We use a online scheduling tool called ScheduleOnce. That tool has the ability to utilize webhooks, per this article , to notify other systems of bookings behind made. What I don't know how to do, nor find the information on apparently, is how do I listen for / consume the POST message in Salesforce? I want to create a record in a custom object whenever a booking is made in that scheduling tool. Not asking for anyone to write any code for me. I just can't seem to figure out the starting point for this. Found plenty of info on how to have Salesforce post to another system but not finding how to consume the message from another system. Thanks!

We have a need for equipment to post status updates to salesforce. Unfortunately the equipment lives on a secure network that will not allow return communication The methods I see all require a request for an auth token and then use that token to post to the rest method.  Is there a way to do this in one shot just straight post to the rest method with a preset token or a combo password api token?


I am using Solaris 10 and so grep options involving -f don't work.  I have two pipe-separated files:   file1:  abc|123|BNY|apple| cab|234|cyx|orange| def|kumar|pki|bird|   file 2:   abc|123| kumar|pki| cab|234   I would like to compare the first two columns of file2 with file1 (search through the entire contents of file1 in first two columns) if they match print the matched line of file1. Then search for the second line of file 2 and so on.   Expected Output:  abc|123|BNY|apple| cab|234|cyx|orange|   The files I have are huge, containing about 400,000 lines, so I would like to make the execution fast.


I have posted a question Which down-voted and closed. Now I want to delete the question. However I am getting error. Why is such a restriction?   Error which I am getting

What circumstances can cause a question or answer to be deleted, and what does that actually mean?    How can a post be deleted? When can't I delete my own post? Can I still see my post even after it's deleted? Can I see a list of my deleted posts? How can I undelete one of my posts? What does deletion mean for a post? How do votes to delete work? What are the criteria for deletion? What else should I know about deleted posts? If I flag my question with a request to delete it, what will happen?       For more information, see the articles about  and  in the .


I started using Ubuntu about 2 years ago and at that time installed 16.04 LTS. A few days ago 18.04 LTS launched. Is it necessary to upgrade to this new version right away, since LTS distro's are supported for 5 years?

I'm following the , but on launching the upgrade tool I get this response:  Checking for a new ubuntu release No new release found   Am I doing something wrong? Is there a workaround?


I'm trying to solve the question:     Ten people are standing are standing in a circle. Find the number of ways to choose $3$ people such that no $2$ of them are consecutive.    I have got the answer to be ${10\choose1}{6\choose2}$, but I'm not sure if this is right.   Please tell me if my answer is correct! If it's not, then where did I go wrong?

If $n$ distinct things are arranged in a circle, then what are the number of ways selecting three of these things so that no two of them are next to each other?


libimobiledevice doesn't work for me. I've got Ubuntu 11.10 and I'm trying to put music on to my iPod Touch 4Gen running iOS 5.0.1.   I have tried every program available in the Ubuntu software center for sycing iPods and I get basically the same response from each one: "[cannot apply changes etc, ect, etc]" I've tried rigorously with Banshee and Rythmbox with no success.   I've even tried running iTunes on Windows XP in VirtualBox with no success. I've tried running iTunes through Wine and it results in an error message saying something along the lines of "[Please install Apple Application Support and then reinstall iTunes]". I am considering Jailbreaking my iPod but I cannot find Absinthe that works with my iPod and with Ubuntu. In addition I'm not sure how ** works with Ubuntu. I'm really in a pickle here.   It would be ever so helpful if I could indeed have some help with this issue.

What ubuntu applications provide support? (guides, how to's, status) Also, specifically, details on support for syncing music to iPhone's and iPod's with the latest OS version:   Can you sync music to apple devices using >iOS4? (iPhone & iPod) What applications allow you to do this and how? (guides, how to's, status)    What has already been established is:   Apple does not support Linux and has no plans to.  provides some support, however it currently does not support music/video synchronization with devices >iOS4. Go to  and scroll to the section titled "" to see if your device version is supported.


I have windows 10 and ubuntu-16.04 installed in dual boot.  I want to get into the Linux universe from time to time and I have a problem that is rather intriguing to me! When I  installed, Ubuntu already has Windows 10 installed with two C: and D: partitions.   To install Ubuntu I created a third partition with on the hard disk and installed ubuntu in dual boot! Until then, everything OK !!  When I opened the Ubuntu OS I can see the disks C: and D: and I can read and write files on them !! But after using the system two or three times, do not know the right, is no longer allowed to read or write the disks through Ubuntu!  What happened?

Whenever I boot Ubuntu, I get a message that it cannot mount my windows partition, and I can choose to either wait, skip or manually mount.  When I try to enter my Windows partition through Nautilus I get a message saying that this partition is hibernated and that I need to enter the file system and properly close it, something I have done with no problem so I don't know why this happens.    Here's my partition table, if any more data is needed please let me know.     Device Boot      Start         End      Blocks   Id  System /dev/sda1            2048    20000767     9999360   83  Linux /dev/sda2        20002814   478001151   228999169    5  Extended /dev/sda3   *   478001152   622532607    72265728    7  HPFS/NTFS/exFAT /dev/sda4       622532608   625141759     1304576   82  Linux swap / Solaris /dev/sda5        20002816   478001151   228999168   83  Linux


If $b_{n+1}=\sqrt{2+b_{n}}$ for $n=1,2,3,\cdots\cdots$. Then $\lim_{n\rightarrow\infty}b_{n}$ is , given $b_{1}=3$   Try: let $b_{n}=2\cos(x_{n})$. Then put into $b_{n+1}=\sqrt{2+b_{n}}$  We have $$2\cos(x_{n+1})=2\cos\bigg(\frac{x_{n}}{2}\bigg)$$  Could some help me how to calculat $\lim_{n\rightarrow\infty}b_{n}$  Thanks in advanced

(Fitzpatrick Advanced Calculus 2e, Sec. 2.4 #12)  For $c \gt 0$, consider the quadratic equation $x^2 - x - c = 0, x > 0$.  Define the sequence $\{x_n\}$ recursively by fixing $|x_1| \lt c$ and then, if $n$ is an index for which $x_n$ has been defined, defining  $$x_{n+1} = \sqrt{c+x_n}$$  Prove that the sequence $\{x_n\}$ converges monotonically to the solution of the above equation.  Note: The answers below might assume $x_1 \gt 0$, but they still work, as we have $x_3 \gt 0$.    This is being repurposed in an effort to cut down on duplicates, see here: .  and here: .


Can the striker be dismissed, Caught, if the ball is deflected off an umpire before that fielder takes the catch?

Will the batsman be dismissed as caught is each of the below scenario:   If the ball hits the arm pad of the batsman and is caught by the fielder. If the ball hits the leg pad first, then hits the bat and is finally caught by the fielder. If the ball hits the bat first, then hits the umpire and is finally caught by the fielder. If the ball hits the bat first, then hits the batting partner and is finally caught by the fielder.


Let $c$ be a positive constant. Suppose I have $X$~$Unif(0,\theta)$ and I wish to test the null hypothesis $H_0: \theta \leq c$ against the alternative hypothesis $H_1:\theta > c$. Suppose I did a sample $X_1,...,X_n$ but I obsrerve them with perturbation - that is, I actually have on hand $Y_1:=X_1+\epsilon_1,...,Y_n:=X_n+\epsilon_n$ where $\epsilon_i$ are i.i.d. ~ $N(0,\sigma^2)$. How should I conduct a hypothesis testing?  Idea: I was thinking of using Likelihood ratio test, since that allows me to do hypothesis testing on a composite null hypothesis. I can take into account the errors in my likelihood function by convolving the uniform with the normal. However, when I want to define critical values, I have difficulty because I have no idea how to approximate the test statistic to any distribution and hence derive rejection regions.  Idea 2: Rao's score test, since here I know how to approximate the test statistic distribution for large sample size, but the only form of Rao's test I know involves point null hypothesis (i.e. testing $\theta = c$) - sadly, my bound $c$ is conservative upper bound, so there is a large chance that $\theta$ is smaller than $c$ and I dont want this case to be a rejection case.  Other ideas would also be appreciated.

Suppose I have a random variable $X$ ~ $Unif(0,\theta)$ where I want to estimate $\theta$. I draw a sample $X_1,...,X_n$.One way is to get a point estimate using e.g.  maximum likelihood estimation via the sufficient statistic $X_{(n)}$.  However, suppose I want a 95% confidence interval of sorts on the value of $\theta$, how should I construct one?  The reason why I am interested in confidence interval is because of the following issue, which is actually my main question (the above prelude on confidence interval is just a suggestion on possible approach). So actually my sample came with some noise, in a sense that I actually observe $X_1+E_1,...,X_n+E_n$ where $E_i$~$N(0,\sigma_i^2)$ independently from each other and from the $X$'s. How should I make some form of statistical estimation about $\theta$? I would prefer some form of confidence estimate.


I'm looking for a full list of currency / money formatting for each locale. I know that for US for example 1500.00 USD would be formatted as  $ 1,500.00   Australian user would see US$ instead of $. Some locales put the sign after the number i.e. 1,500.00 $, other uses minus sign before the currency sign i.e. -$ 1,500.00. Some use space as grouping i.e: $ 1 500.00 and etc and etc  The closest list I could find is   But it does not include the position of the minus sign and the currency symbol. Is there any standard that I can refer to in order to format money correctly for each locale?  Thank you!

Is there a suggested, single location to place the currency symbol every time for any given locale?  For example, always on the left with a space before the amount like this:  R 10.00 $ 10.00 € 10.00 ¥ 10.00   Is this acceptable even in instances when the currency symbol is usually placed to the right of the amount, or should you keep track of the placement per locale?  Also, what is the best way to handle currencies with odd unicode characters when you plan on targeting devices that don't support the displaying of these characters? Do you default to using the three letter international code? If you do then do you still obey left-or-right placement or can you place all on the left?


I tried everything, including zeroing out first few sectors, using dd. But these operations have no effect whatsover. I am using Samsung micro SD to SD card adapter to connect to laptop card reader. The microSD card is of Sandisk (16GB class 10). I have attached sceenshot. Please help!!!

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.


using System.Collections; using System.Collections.Generic; using UnityEngine; using UnityEngine.UI;  public class replicate : MonoBehaviour {      public void replicateCube(InputField T)     {         int H = int.Parse(T.text);           for (int i = 0; i < H; i++)         {              GameObject prefab = Resources.Load("Cube") as GameObject;             GameObject go = Instantiate(prefab) as GameObject;             go.transform.position = new Vector3(0, i*5, 0);          }     } }

Since many users are facing the NullReferenceException: Object reference not set to an instance of an object error in Unity, I thought that it would be a good idea to gather from multiple source some explanation and ways to fix this error.  Symptoms I am getting the error below appearing in my console, what does it mean and how do I fix it?  NullReferenceException: Object reference not set to an instance of an object