I know that * references all files excluding hidden files, how to reference all files including hidden files whose names begin with a . in bash?

I want to glob every hidden file and directory, but not the current (.) and parent directory (..).  I am using bash.  Observe current behaviour:  $ ls -a .  ..  ...a  ...aa  ..a  ..aa  .a  .aa  .aaa  a $ echo * a $ echo .* . .. ...a ...aa ..a ..aa .a .aa .aaa   I would like .* to behave like this  $ echo .* ...a ...aa ..a ..aa .a .aa .aaa   There is the shell option dotglob  $ shopt -s dotglob   that works in a way; now I can use * to glob everything (hidden or not) but not . and ..  $ echo * ...a ...aa ..a ..aa .a .aa .aaa a   but now I can't differentiate between hidden or not. Also, .* still globs . and ..  $ echo .* . .. ...a ...aa ..a ..aa .a .aa .aaa   Is there a way to make .* not expand to . and ..?


I am working on a regression and I have a factor variable "Marital Status"  Marital status has 5 levels: Single, Married, Divored, Widowed, Other (don't ask me what constitutes someone being an 'other')  When I put this into R it will turn this one variable into 5-1=4 dummy variables and will give me this output     with divorced as the baseline.   My question is, can I only use the significant dummy variables? I would drop the variables for 'other' and 'widowed' and keep 'married' and 'single'

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.


Is there any race that can make let me play as a fox? Either an anthropomorphic fox, or (preferably) a human looking race with fox ears and tail, like an inumimi if you know what that is.

Can you play a  or  (fox or cat beings, respectively) in D&D 5th edition? I have never played,  but wanted to use one of my RP characters for D&D.  If not, are there any existing races that are similar?


This is my code:  \documentclass{article} \usepackage{amsthm} \theoremstyle{definition} \renewcommand{\thesection}{Section \arabic{section}} \newtheorem{theorem}{Theorem}[section]  \begin{document}  \section{}  \begin{theorem}     A theorem. \end{theorem}  \end{document}   This produces:  Section 1 Theorem Section 1.1. A theorem.  I would like it to say:  Section 1 Theorem 1.1. A theorem.  How can I do this?  Thanks.

\section{Introduction}   gives something like  1. Introduction  How can I rather obtain the following header?  Section 1. Introduction


Is it possible to create a planetary-volumetric style clouds on the faces of a sphere? Every attempt I try always comes out to look too 2d when approaching the image closely. I tried the volume output but as it says, it only keeps the stuff inside the circle and looks oddly flat on the top. If there is anything you can think of that would help thanks.

I created a planet in blender a while ago, and now i'm interested in adding volumetric clouds instead of using a 2D texture. I considered adding a bump node to my material, but then it would remove the realism in the image.  This is what I've created:    This is the effect I want to create:      Any thoughts?


As far as I know, every desktop/server distribution of Linux has Perl (and core modules) installed by default, AIX and Solaris (IIRC) also do.   By "by default" I mean that even the most lightweight variant has it.  I haven't worked on BSD or similar ones, do they come with Perl?  Motivation: I'm trying to figure out if encouraging people in my team to use Perl instead of awk/sed/other text utils would make sense.   Note:  does't answer my question. Portability it's not my main concern here, availability out of the box is. Even if all unix-like systems have awk/sed I would still prefer Perl.  Note: also, by Perl I mean Perl 5.8+

Can someone put these tools in order of portability? Which of these is certain to be found on even the most minimal *nix systems? Is any of them 100% sure to be present? My guess is that the order is the following:   awk sed sh perl   While I imagine there are systems which don't default to a bourne shell, some shell will be present as the default, will that always be at /bin/sh? Presumably not if it's not a bourne-type shell. Both  and  have pages explaining them on the POSIX specification so presumably they will always be present. Is that so? Can I be sure that both will be installed on any *nix? Including embedded systems?


What sanitisation should be done to form inputs before inserting into a MySQL database?  I have just 2 user-entered inputs in my PHP web application which will be sent to a series of successive pages (both via GET and via POST), before they are eventually stored into a MySQL database.  Both are text inputs (e.g., <input type="text />").  The first is a field which should be filled by a Google maps api javascript, but which I nevertheless obviously can't trust; the second is a freely entered username field, which at the moment only has a restriction on the string length.  What server-side checks or transformations should I perform on the values of these two fields before inserting them into the database, to prevent malicious actions, or other errors perhaps with special characters?  I am using PDO prepared statements for all my database operations, like:  $id = '1234567'; $username = 'John Smith'; //Could be weird characters like "Seán Óg Ó hAilpín"! $Query = $db->prepare("INSERT INTO `MyTable` (`id`, `username`) VALUES (?,?)"); $Query->execute(array($id, $username));   If the values should be encoded or transformed, how should they be unencoded before displaying in HTML?  (All my other form variables are the result of choices from drop-down select menus, and I thought of validating & sanitising their values by simply exiting the receiving script if any of them was not (!===) any of the limited number of variables I am expecting.  I'm hoping this 'whitelisting' method would be sufficient for those.)

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


I have a file test.xml (shown below).  This grep works:    grep '<appointment-id internal:ref=1.2.3/>' test.xml   Output is:      <appointment-id internal:ref=1.2.3/>   But this fails:  grep "$(grep '<appointment-id internal:ref=1.2.3/>' test.xml)" test.xml   Output is:  grep: invalid character range   Contents of test.xml:  <note>     <to>Jim</to>     <from>John</from>     <heading>Reminder</heading>     <body>Some text</body>     <appointment-id internal:ref=1.2.3/> </note>   I have put both grep commands (the simple one and the nested one) into a script with set -x.  Here is an exact copy & paste of that script:  set -x grep '<appointment-id internal:ref=1.2.3/>' test.xml grep "$(grep '<appointment-id internal:ref=1.2.3/>' test.xml)" test.xml exit 0   and here is its output:  ++ grep '<appointment-id internal:ref=1.2.3/>' test.xml     <appointment-id internal:ref=1.2.3/> +++ grep '<appointment-id internal:ref=1.2.3/>' test.xml ++ grep '    <appointment-id internal:ref=1.2.3/>' test.xml grep: invalid character range ++ exit 0

Why does the following gives the line I am searching:    grep '<appointment-id internal:ref=1.2.3/>' test.xml   OUTPUT is <appointment-id internal:ref=1.2.3/>     While the following breaks it into 2 lines?    a=($(grep '<appointment-id internal:ref=1.2.3/>' test.xml))   for i in "${a[@]}"; do       echo "checking $i"        grep  -n "$i" delete.xml done       The output is:     checking <appointment-id checking internal:ref=1.2.3/>   The file is:    <note>       <to>Jim</to>       <from>John</from>       <heading>Reminder</heading>       <body>Some text</body>       <appointment-id internal:ref=1.2.3/>  </note>


In PHP 7, what is the difference between using self and $this? When is each appropriate?

In PHP 5, what is the difference between using self and $this?  When is each appropriate?


I want to show that the set of all polynomials with rational coefficients is countable.   I know that to prove this I need to find a mapping $f$ from the natural numbers to this set that is a bijection. But I'm struggling conceptually of how to think of this. In fact, my intuition is that this isn't even true since can't we plug in an uncountable set of numbers into our polynomial? It's because of this thought that I can't even think of what a bijection would be like. If anyone could help untangle these conceptual issues I'm having that would be good -- I don't necessarily need a proof of the claim, though that's fine too.  Edit: not really a duplicate.

Problem: Show that the set of polynomials with rational coefficients is countable.   Idea: We know that the set of rational numbers is denumerable. This implies that the set of rational numbers is countable. We also know that the degree that each polynomial can be is a natural number (I think, and I'm not sure how to word this.) Therefore, I think we can reason through this somehow, by showing that the plane $Q X N$ Is denumerable. I'm just not sure how to do this. Any ideas.  Note: this is for my introduction to proofs class study quide. So, I would prefer not to go to over the top.


So part of my site is asynchronously loaded with javascript. This part contains links to products. All these links also exist in my sitemap.xml.   I've tested with Googlebot Fetch and it doesnt see these links, probably because of the asynchronous javascript that fetches them from an api.  So my question is, does googlebot treat internal links differently from sitemap.xml links?   If a product exists both as an internal link on my page and in sitemap.xml is it more valuable than if it just existed in my sitemap.xml ?

We use a  on Stack Overflow, but I have mixed feelings about it.  Web crawlers usually discover pages from links within the site and from other sites. Sitemaps supplement this data to allow crawlers that support Sitemaps to pick up all URLs in the Sitemap and learn about those URLs using the associated metadata. Using the Sitemap  does not guarantee that web pages are included in search engines, but provides hints for web crawlers to do a better job of crawling your site.  Based on our two years' experience with sitemaps, there's something fundamentally paradoxical about the sitemap:  Sitemaps are intended for sites that are hard to crawl properly. If Google can't successfully crawl your site to find a link, but is able to find it in the sitemap it gives the sitemap link no weight and will not index it!  That's the sitemap paradox -- if your site isn't being properly crawled (for whatever reason), using a sitemap will not help you! Google goes out of their way to make :  "We cannot make any predictions or guarantees about when or if your URLs will be crawled or added to our index"  "We don't guarantee that we'll crawl or index all of your URLs. For example, we won't crawl or index image URLs contained in your Sitemap."  "submitting a Sitemap doesn't guarantee that all pages of your site will be crawled or included in our search results"   Given that links found in sitemaps are merely recommendations, whereas links found on your own website proper are considered canonical ... it seems the only logical thing to do is avoid having a sitemap and make damn sure that Google and any other search engine can properly spider your site using the plain old standard web pages everyone else sees. By the time you have done that, and are getting spidered nice and thoroughly so Google can see that your own site links to these pages, and would be willing to crawl the links -- uh, why do we need a sitemap, again? The sitemap can be actively harmful, because it distracts you from ensuring that search engine spiders are able to successfully crawl your whole site. "Oh, it doesn't matter if the crawler can see it, we'll just slap those links in the sitemap!" Reality is quite the opposite in our experience. That seems more than a little ironic considering sitemaps were intended for sites that have a very deep collection of links or complex UI that may be hard to spider. In our experience, the sitemap does not help, because if Google can't find the link on your site proper, it won't index it from the sitemap anyway. We've seen this proven time and time again with Stack Overflow questions. Am I wrong? Do sitemaps make sense, and we're somehow just using them incorrectly?


I am fairly new to Java and am in need of help with my If/Else statement. Basically I want to make it so that if the person types in n or no do one thing, or if the person puts in y or yes, do another thing, and if the person doesn't put in n, no, yes or y than do a different thing. But no matter what the user puts in, it acts as if they did not put in n, no, yes or y. How can I fix this?   This is my code so far:  public class Main  {  public static void main (String[] args)  {     Scanner userInputScanner = new Scanner(System.in);     String [] charName = {"John", "Bob", "Sam"};     Random random = new Random();     int charNameChoice = random.nextInt(charName.length);     System.out.println("Random char selected: " + charName[charNameChoice]);     System.out.println("Y N Question1");     System.out.println("You can input y, yes, n or no");     String questionOneAnswer = userInputScanner.nextLine();     if (questionOneAnswer == "n" || questionOneAnswer == "no")     {         System.out.println("I disagree");     }     else if (questionOneAnswer == "y" || questionOneAnswer == "yes")     {         System.out.println("I agree");     }     else     {         System.out.println("Invalid");     }   }  }

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?


Surprisingly, I never came across a repeating decimal, which did not include the last digit, so I'm wondering if this would even be a valid notation?  $$0.\overline{0}1$$  So the following statement would be true?  $$1 - 0.\overline{9} = 0.\overline{0}1$$  Thanks for clarification.

Does $1.0000000000\cdots 1$ (with  an infinite number of  $0$ in it) exist?


I have a 256gb SSD and a 1tb HDD on mu laptop. I want to create a dual boot and add a linux OS (with ubuntu) on my SSD. but, I have only 160 gb free out of the 256, so i'd rather install the OS and only the OS on the SSD and then use part of the HDD for the linux. I mean I want to use the SSD only to store both systems, and then also split the hdd and use it for both of them as well. Is it possible? Can it ruin something? the use of one ssd for 2 systems? How can I split the HDD to both of them? I'll try to be more specific. As I said I have free 160gb out of 256gb on my C:\ SSD which already got Windows on it. I want to also install Linux on it. But when i'll be working on Linux, i'll probably download stuff, apps, documents, create projects and etc, which will consume memory and I don't want it to consume memory of the C:\ SSD, I want it to consume memory from my D:\ HDD which got free 1GB. In that way I won't be "scared" to download and create many things that will consume alot of space because I won't care about the space because I got plenty of it on my HDD unline my SSD which got only 160 free gb, and i'll allocate another 50gb for the linux which means it will reduce to 110 free gb, and I don't want it to be reduced any more and I would prefer to use the space that on my 1TB HDD for my projects and things. Thanks.

I'm a new Linux user and a Windows convert. I tried Ubuntu (Dapper Drake) a few years ago and liked it quite a bit, and I'm in the process of installing Xubuntu 13.10 along side Windows7 on my brand new SSD! At this point, Windows is still being installed because I need it to be, but Linux is getting installed because I want to use it! I've done quite a bit of research and I've toyed around with Linux before, but I'm still a newbie and I have a few questions concerning partitions and program installations..  My new SSD isn't huge (120GB Samsung 840 EVO), and I'll be using my old 800GB HDD as a secondary drive. The thing is, I plan on using Linux as much as possible; only switching over to Windows7 when I absolutely need to. Because of this, I'll be doing a 50:50 split of my SSD for each OS (60GB for Linux, 60GB for Windows). I'm also planning on splitting my old, 800GB HDD into 3 partitions: some space for extra linux programs, some space for extra windows programs, and then a shared NTFS partition for all of my data (music, videos, documents, etc.).  So to sum up my space situation:   ~60gb SSD + 200gb HDD for Linux..  ~60gb SSD + 200gb HDD for Windows.. ~400gb shared NTFS..   This leads me to my questions.. While I have a fairly good idea of how my Windows setup will work (60gb C: drive, 200gb D: drive, etc.), the Unix/Linux directory structure is still very new to me and is making this process a little bit confusing. I know that it's possible (and common) to partition your "/" directory and "home" directory separately, and - as I understand it - the "/" partition is meant to contain system specific programs and data, while the "home" partition contains the programs and data of the various users.  However, I've also heard that most (if not all) of the programs that you install from repositories using APT are installed into the "/" directory. As someone who works with music/art programs and plays games (which can take up a LOT of space), this leads me to believe that I'll need a large "/" partition!  I've also read (from here: ) that the "home" directory is "the place where all the user-specific files, your data in other words, are stored. It is roughly equivalent to the “My Documents” folder on a MS Windows desktop". But, as I mentioned above, I intend to keep all of my non-OS-specific data (music, documents, videos, etc.) on my ~400gb shared partition, anyway. This really leads me to believe that I don't need a big home partition at all and that I should focus on partitioning as much space as possible for "/". And still, I've heard other people claim that you only need around 10gb of space for your root partition!?   Edit: Also, I just found out that programs like Steam and Wine take up space inside the "home" directory.  So, what should I do? I basically have 60gb SSD and 200gb HDD space for holding nothing but Linux programs. All of my data will be going onto my 400gb shared NTFS partition, so is it even worth making separate partitions for "/" and "home"? If I install both root and home on my 60gb SSD, how can I also use the extra 200gb of HDD space for more Linux programs? Can I expand root across multiple drives somehow, or maybe have a symlink or something that connects the two drives together?  As I said before, I'm still a major Linux newbie, so there may be something that I've completely misunderstood or overlooked. As someone who does a lot of art/music creation and gaming on my PC, I tend to use up a lot of program space quite quickly, especially since games and music libraries just keep getting bigger and bigger every year! Thanks for the help, I'm looking forward to learning more about Linux! :]


Why are there so many upvotes and reputation for any unicorn-related post? I just cannot understand it.

Catchphrases and concepts that spread from person to person are known as [memes], which, courtesy the Internet, can now explode across the Earth like a highly contagious virus (hence "going viral"). As with their real-life counterparts, some infectious diseases are global (pandemic), while others are endemic to specific regions. Stack Overflow, and now even more predominantly Meta Stack Exchange, have seen more than their fair share of these pathological social constructs spread through the user base. They are now ingrained units of our collective culture as SOpedians (a term which I hate, by the way). Just as travelers' immune systems can be assaulted by new diseases in new places, new users are increasingly likely to be miffed by an ingrained meme and left sitting scratching their heads. I therefore propose that this space be used to document the memes endemic to Stack Exchange's culture. Each meme should be listed in a separate answer and I hope that we as a community will be able to provide greater context to each one. Please actually explain each meme in a way understandable to those not already in the know. Especially considering that a lot of these memes aren't really understandable to newer users who weren't around in the early years of the network, or are based on system features that no longer exist.  On other Stack Exchange sites          [memes]:


It seems that Harry's parents left him a pretty sizable fortune. They were pretty young when they had Harry and when they died. I dont remember much talk about their professions. How did they manage to amass such a fortune at such a young age?

So, at the beginning of Harry Potter, Harry is found to have a large vault of gold at Gringotts. Where did all of that money come from? What did James (I assume it came from him, as Lily was muggle-born, and they were both young) do to get all of that cash?


Given some compact subset of the plane and a symmetry of that subset, i.e. a bijective isometry from that set to itself, it seems that in any example I come up with the symmetry can be written as some combination of translations, rotations, and reflections - in other words it may be extended as a symmetry of the plane. This leads me to conjecture that this is always the case. Indeed,  MathOverflow question seems to cite a stronger result, but I cannot see what the referenced material has to do with this fact.

I know that the following theorem holds true:  Let $S$ be a subset of $\mathbb R^n$, and let $f:S\to \mathbb R^n$ a map such that $d(p,q)=d(f(p),f(q))$ for every $p,q \in S$ (here $d$ is the usual euclidean distance). Suppose that $0 \in S$ and $f(0)=0$. Then $f$ can be extended to an orthogonal transformation of $\mathbb R^n$.  I have two questions:   Can someone give me a reference of a proof of this theorem? I believe that the previous theorem holds true also if we change $\mathbb R^n$ with $\mathbb C^n$ and "orthogonal" with "unitary", with nearly the same proof. Does it holds true also in the $ \ell^2$ space? With the same proof?


I'm trying to create alertdialogs through a custom dialogframent class  public class Dialogs extends DialogFragment {     @Override     public Dialog onCreateDialog(Bundle saveInstanceState) {         AlertDialog.Builder alert=new AlertDialog.Builder(getActivity());          //additional custom layout here(skipped)          alertDialog=alert.create();         return alert.create();     }      public static Dialogs newInstance(String title, String fields, String buttons) {         Dialogs d = new Dialogs();         Bundle args = new Bundle();         args.putString(TITLE,title);         args.putString(FIELDS, fields);         args.putString(BUTTONS,buttons);         d.setArguments(args);         return d;     }      public List<Button> getButtons() {         return this.buttons;     }      public AlertDialog getDialog(){         return alertDialog;     }   I am calling it in my main activity via  public void AddNewTask() {     Dialogs my_dialog = Dialogs.newInstance("Add New Task",NEW_TASK,NEW_TASK_BUTTON);     my_dialog.getDiag().show(); }   getting  java.lang.NullPointerException: Attempt to invoke virtual method 'void android.app.AlertDialog.show()' on a null object reference   I have a hunch it's that the arguments were put after the d was created. So the argumnets didn't pass through? Any help is appreciated  Edit: This is not a question of what is a nullpointer exception. I understand very well what it is. I have solve the problem  for those that possibly have similar issues in the future. I changed the way the dialog was launched inside main activity. It seems like I was missing a fragmenttransaction.   final Dialogs my_dialog=Dialogs.newInstance("Add New Task", NEW_TASK, NEW_TASK_BUTTON);         FragmentTransaction  ft = getFragmentManager().beginTransaction();         my_dialog.show(ft, "dialog");

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


What are the names of power supply connectors in this picture?

I was looking at this  which has strange interface pins. I have never seen anything like it.  I wonder how am I supposed to connect to them. What connectors can I use and what's special about them? Is it good for RF stuff for example? What are they called? I could research more if I knew what these pins are called.  Edit: Answered in the comments: They are turret pins where you wrap a wire and solder to.


The Code below gives the output of reverse diagonal values in a 2d Array. Output is:  3,5,7  int[,] array2d2 = {      {1,2,3},     {4,5,6},     {7,8,9}  };  int i = 0; while (i <= 2) {     for (int j = 2; j >= 0; j--)     {         Console.WriteLine(array2d2[i,j]);         i++;     } }  If my understanding is right, the increment operator(i) in the nested for loop, breaks the for loop by moving to the while loop and increment it by 1 and then continue the iteration. It already gave the output I wanted. My question, Is this the right way or my understanding is wrong? I'm a beginner in C#.

If I have a for loop which is nested within another, how can I efficiently come out of both loops (inner and outer) in the quickest possible way?  I don't want to have to use a boolean and then have to say go to another method, but rather just to execute the first line of code after the outer loop.  What is a quick and nice way of going about this?  I was thinking that exceptions aren't cheap/should only be thrown in a truly exceptional condition etc. Hence I don't think this solution would be good from a performance perspective.  I don't feel it it is right to take advantage of the newer features in .NET (anon methods) to do something which is pretty fundamental.


Suppose that the sole developer of a niche open source project available from an official Ubuntu repository gets to sneak a malicious commit into their project, making the otherwise useful program act as a keylogger and send the collected data  to the project's server along with benign and expected data queries, or perform any other similar and clearly destructive activity.  What layers of security does Canonical provide to avoid that? Is the code available from the official repos independently audited? What if the package maintainer is in cahoots with the developer, or is the same person?

I read in the news about all the malware that is infecting Android OS. The malware is in Google's App Store and people are unknowingly downloading and installing it.  As I understand, Ubuntu's Main repository is safe for me to download from (I won't be infected with malware from doing so) because Canonical engineers review the software. But what about other repos, most notably the Universe repository? Does the Universe repo receive any sort of review to protect from malware? Is it advisable to avoid the Universe repo for fear of unknowingly downloading malware from it?  I've read PPAs are particularly dangerous because they are not reviewed. I'm assuming it is perfectly safe to use the Google Chrome PPA however.  So if I use nothing but the Main & Universe repositories and Google Chrome PPA, will I be protected from unknowingly downloading malware?   If Ubuntu does gain hundreds of millions of users like Mark Shuttleworth predicts, won't Ubuntu PPAs become the malware problem for Ubuntu like Google's App Store is today for Android?


I am getting following error message when I am trying to install wireshark using:  sudo apt-get install wireshark   output:  Err http://us.archive.ubuntu.com/ubuntu/ oneiric/universe libsmi2ldbl amd64 0.4.8+dfsg2-4   Could not connect to 10.1.101.150:3128 (10.1.101.150), connection timed out   Please help me to come out of this problem...

I'm trying to update my system using apt-get, but it's giving me this error  Err http://bd.archive.ubuntu.com raring Release.gpg          Could not connect to bd.archive.ubuntu.com:80 (116.193.170.18), connection timed out Err http://bd.archive.ubuntu.com raring-updates Release.gpg   Unable to connect to bd.archive.ubuntu.com:http: Err http://bd.archive.ubuntu.com raring-backports Release.gpg   Unable to connect to bd.archive.ubuntu.com:http: Reading package lists... Done W: Failed to fetch http://bd.archive.ubuntu.com/ubuntu/dists/raring/Release.gpg  Could not connect to bd.archive.ubuntu.com:80 (116.193.170.18), connection timed out W: Failed to fetch http://bd.archive.ubuntu.com/ubuntu/dists/raring-updates/Release.gpg  Unable to connect to bd.archive.ubuntu.com:http: W: Failed to fetch http://bd.archive.ubuntu.com/ubuntu/dists/raring-backports/Release.gpg  Unable to connect to bd.archive.ubuntu.com:http: W: Some index files failed to download. They have been ignored, or old ones used instead.   I am not a Ubuntu master but I can understand this is not a computer error. Any clues on how to fix it?


Prove the following results for the eigenvalues of an $n \times  n$ matrix $A$:   (a) $0$ is an eigenvalue for $A$ if and only if $A$ is not invertible.  (b) $A$ and $A^T$ have the same eigenvalues.

Let $ \sigma(A)$ be the set of all eigenvalues of $A$. Show that $ \sigma(A) = \sigma\left(A^T\right)$ where $A^T$ is the transpose matrix of $A$.


in this code snippet, I could not use obj before declaration    const obj = {      value : 10,      x : obj }    while here I could    const obj = {      func : () => console.log(obj.value),      value : 10, } obj.func();    How could the second compiles but the first fail? actually, I wonder why any of them compiles since I used obj before it was instantiated, as I understand (I may be wrong) first the right side first evaluated, and then assign the result to the variable(obj)

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


Let $R = \mathbb Z[x]$, a polynomial ring over $\mathbb Z$, and $\mathfrak m$ be any maximal ideal of $R$. How do we show that $R / \mathfrak m$ is a finite field? I know that the fact that it is a finite field directly follows, but not sure about the finite part.

Suppose $k$ is a field that is finitely generated as a ${\mathbb Z}$-algebra.  (That is, $k$ is a quotient of ${\mathbb Z}[X_1,\dots,X_n]$ for some $n$). Does it follow that $k$ is finite?


Lots of things blow up near planets in Star Wars (Coruscant in Episode III being an obvious example). Why doesn't this end up more like the movie Gravity?

I was recently watching Episode 3 and a few clone wars episodes, and I found myself thinking during the opening battle between the Republic and General Grievous' forces above Coruscant, on a planet so densely populated where potentially thousands of inhabitants can be killed from a drifting capital class ship with a decaying orbit during space battles what defenses are in place?  Is there any instances of some form of emergency services that tractor beam chunks of debris to safe landing places or repulsor towers that can slow or suspend it until it can be taken apart safely? Even disintegration lasers or emergency force field generators like the types deployed on Hoth as they must have the energy output capable of sustaining it. This IS the galactic capital so must have some advanced tech at its deposal. Even now in our own development humans have certain preventative measures for all types of threats and ways of tracking them, plus responses or fall back plans.


I already apply the media query to my website, but the problem is that I can't center the container form. If I use left in one of my media query the other does not center it and it cause to not be able to center it. I also include the cols in media query but it can't help it. I also try to configure the .container form but but tablet or don't be in center please help.. @media only screen and (min-width: 320px) and (max-width: 480px) { .container form{     left: inherit;     position: relative; } .form {     grid-template-columns: 1fr;   } }  /* ------------------------------------For Tablet------------------------>>>>>  */  @media only screen and (max-width: 780px) {     .container {         left: -150px;         position: relative;     }     .form {         grid-template-columns: 1fr;     } }

How can I horizontally center a
 within another
 using CSS?

Foo foo


I'm trying to delete a driver that is giving me issues with some games, I've tried LockHunter, System Monitor, Unlocker, Proccess Explorer but either none of them can delete it nor can they find what program is using the file, can I get some help?

When I try to delete the file, using the GUI it says      The action cannot be completed because the file is open in another   program   And using the del /f /q command line it says     Access is denied   I have tried unlocking the file with Unlocker, as well as trying to locate which process is using the file with the Resource Monitor or the Process Explorer, but no locking handle was found in either case.  I am able to rename or move the file, but not to delete it or change its content.


Say in a certain population one person is infected with a contagious virus. To prevent the virus from spreading the government tests the entire population whether one individual has this disease or not. The test is 99.9% accurate, but not 100%. Is a certain person, whom is tested positive, infected with the virus? One might say yes, but the test could be wrong.  In fact let's think about this problem logically. When the entire population consists of 10,000 people, chances are that 10 people will get a positive result and in 9 out of those cases it is a false positive. In all of a sudden the 99.9% certainty dropped to 10%...  I won't get too mathematical here. But when a diagnosis is not a hundred percent certain, what can be said about the person having the disease? Does he have the disease or not? Or both? Perhaps both states or possible at the same time?

I'm trying to wrap my head around the result of Bayes Theorem applied to the classic mammogram example, with the twist of the mammogram being perfect.  That is,  Incidence of cancer: $.01$  Probability of a positive mammogram, given the patient has cancer: $1$  Probability of a positive mammogram, given the patient does not have cancer: $.01$  By Bayes:  P(cancer | mammogram+) = $\dfrac {1 \cdot .01}{(1 \cdot .01) + (.091 \cdot .99)}$  $ = .5025$  So, if a random person from the population takes the mammogram, and obtains a positive result, there is a 50% chance they have cancer? I'm failing to intuitively understand how the tiny 1% chance of a false positive in 1% of the population can trigger a 50% result. Logically, I would think a perfectly true positive mammogram with a tiny false positive rate would be much more accurate.


First time homeowner and newbie DIY-er here. I'm replacing the light fixture in our bathroom and there's no junction box behind the wall, but I think I'm seeing insulation in there too. There's a stud directly to the left of the circular hole (where the previous fixture had two screws into the stud, and two screws into the drywall). Do I need to put a junction box in there?  It seems unsafe not to.

I just removed two bathroom vanity lights to replace them and discovered that there was no junction box behind either. One light was mounted over a stud and the other was right next the a stud.   At first I thought I could use old work pancake boxes, but the problem is that in both cases, the in-wall wiring runs directly over the stud. So there's not really room to even fit a pancake box in there. I could move the entire fixture to the left or right, but then my fixture is off center and I'll have a hole to patch where it used to be mounted which might not even be possible since the romex runs over the stud where drywall would need to go.  Any ideas on how to proceed?  (Also curious why the romex would even be run like this instead of through the studs? It is an exterior 2x6 wall, FWIW).


The question referred from this discussion   I understand the proof of the Leems.But i still don't get "Then almost all x ∈ R belong to at most finitely many of the E_Ks"? i understood that if x belongs to infinitely E_k then the set contain all such x has measure 0 but how it implies finitely many x's belongs to that set? or infinitely many x ∈ R belong to at most finitely many of the Ek's? how i can get a contradiction?  THanks in advance for the help.

The Borel-Cantelli Lemma in  seems to be a sort of "corollary" of the .  It says:  "Let $(E_k)_{k=1}^{\infty}$ be a countable collection of measurable sets for which $\sum_{k=1}^{\infty} m(E_k) < \infty$. Then almost all x $\epsilon \ \mathbb{R}$ belong to at most finitely many of the $E_k$'s"  I don't get three things:   "Then almost all x $\in \ \mathbb{R}$ belong to at most finitely many of the $E_k$'s"   What does that mean? Since the Borel-Cantelli Lemma comes after the "almost everywhere" definition, I guess: $\exists \ Z \ \subset \mathbb{R}$ s.t. $m(Z) = 0$ and $\forall x \ \in \ \mathbb{R} \setminus Z$, x belongs to $(E_{j}, E_{j+1}, E_{l}, ..., E_{m})$.   In the proof, one can see the $m(\limsup \ E_k) = 0$ part, stated as $m(\cap_{n=1}^{\infty} [\cup_{k=n}^{\infty} E_k]) = 0$. For some reason, $m(\cap_{n=1}^{\infty} [\cup_{k=n}^{\infty} E_k]) = 0$ implies that "Therefore almost all x $\in \ \mathbb{R}$ fail to belong to $\cap_{n=1}^{\infty} [\cup_{k=n}^{\infty} E_k]$ and therefore belong to at most finitely many $E_k$'s"   Okay, why? What is the contradiction if almost all $x \epsilon \ \mathbb{R}$ belong to all the $E_k$'s? Or a countably infinite subcollection?   What is the significance of this? Why not just state the Borel-Cantelli Lemma as "Let $(E_k)_{k=1}^{\infty}$ be a countable collection of measurable sets for which $\sum_{k=1}^{\infty} m(E_k) < \infty$. $m(\cap_{n=1}^{\infty} [\cup_{k=n}^{\infty} E_k]) = 0$"?


Let $R$ be a ring such that ${x^2}-x$ $\in$ $C(R)$ $\forall$ $x$ $\in$ $R$. Prove that $R$ is commutative.  I have tried like this :  Let $x$, $y$ $\in$ $R$. So , ${x^2}-x$ , ${y^2}-y$ $\in$ $C(R)$. Now, we have to prove that $xy$ $=$ $yx$. Now, $y({x^2}-x)$ $=$ $({x^2}-x)y$ ,  $x({y^2}-y)$ $=$ $({y^2}-y)x$. From these , I got that $x(x-y)y$ $=$ $y(x-y)x$ . Now I am stucked. Please help.

Let $R$ be a ring such that   $$ x^2-x \in C(R) \quad \forall x \in R,$$   where $C(R)$ is the center of $R$. Prove that $R$ is commutative.   I cannot find any route to proceed. How can I start? Please give hints instead of full solution.


This is probably a typical beginner question.  Imagine I buy today a stock for 10$. The market gods are good to me and one day later it has a value of 100$, at which point I sell it and cash out.  Are those 90$ profit I made free money? Where do they come from?

Basically I am new to stock trading and neglect to see the differences between trading stocks and betting on sports. Basically I am "betting" on which company will do well, and this can change due to "upsets" just like in sports, but my main question is this: Is new money actually created in the stock market, or am I just gaining money that someone else has lost? The answer must be money is being created or "destroyed" because how would the stock market ever be down overall or up overall, but I just can't seem to wrap my head around it. Like stocks have no inherent value, unlike say something like gold which I could wear as a chain or jewelry. But the only reasons to own a stock that doesn't pay dividends is to sell again at a later point, unless you manage to get 51% of them which I doubt most traders try to do. So am I missing something or what? Any help would be greatly appreciated thanks!


My area of expertise is not Java. I develop in other languages on other platforms.  Right now I'm developing a series of Java servlets for a project. The servlets are to run on a CentOS server running FileNetP8.  I actually got all of the planned items finished and running.  Now when I am trying to add a few more services, the library I came across is available via Maven. I have no idea what Maven is. Read up on it today. Created a test project to try it out.  My development environment is Eclipse Photon on Windows 10.  Now my problem is I can't figure out how to add the Filenet JARs to the project. I can't upload them to some Maven repo. Searching the Web says to add them to the local repo, but I don't understand how to do that to the Local repo in Eclipse's builtin Maven.  I think that the JARs don't need to be packaged within the deployment WAR because the app will be deployed to the Websphere server that runs Filenet so they should be available on it. Should I add them as external JAR references to get the project to compile?

How do I take a jar file that I have and add it to the dependency system in maven 2?  I will be the maintainer of this dependency and my code needs this jar in the class path so that it will compile.


I am using ubuntu 13.10 on evaluation board and my internet is not working. Also i need to install softwares and apt-get install is also not working.  Terminal says :  E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?  source :

I'm trying to install phpMyAdmin using sudo apt-get install phpmyadmin but encountering this error  Err http://gb.archive.ubuntu.com/ubuntu/ precise-updates/main mysql-common all 5.5.34-0ubuntu0.12.04.1   404  Not Found [IP: 194.169.254.10 80] Err http://security.ubuntu.com/ubuntu/ precise-security/main mysql-common all 5.5.34-0ubuntu0.12.04.1   404  Not Found [IP: 91.189.91.15 80] Err http://security.ubuntu.com/ubuntu/ precise-security/main libmysqlclient18 i386 5.5.34-0ubuntu0.12.04.1   404  Not Found [IP: 91.189.91.15 80] Err http://security.ubuntu.com/ubuntu/ precise-security/main mysql-client-core-5.5 i386 5.5.34-0ubuntu0.12.04.1   404  Not Found [IP: 91.189.91.15 80] Err http://security.ubuntu.com/ubuntu/ precise-security/main mysql-client-5.5 i386 5.5.34-0ubuntu0.12.04.1   404  Not Found [IP: 91.189.91.15 80] Err http://security.ubuntu.com/ubuntu/ precise-security/main mysql-client all 5.5.34-0ubuntu0.12.04.1   404  Not Found [IP: 91.189.91.15 80] Failed to fetch http://security.ubuntu.com/ubuntu/pool/main/m/mysql-5.5/mysql-common_5.5.34-0ubuntu0.12.04.1_all.deb  404  Not Found [IP: 91.189.91.15 80] Failed to fetch http://security.ubuntu.com/ubuntu/pool/main/m/mysql-5.5/libmysqlclient18_5.5.34-0ubuntu0.12.04.1_i386.deb  404  Not Found [IP: 91.189.91.15 80] Failed to fetch http://security.ubuntu.com/ubuntu/pool/main/m/mysql-5.5/mysql-client-core-5.5_5.5.34-0ubuntu0.12.04.1_i386.deb  404  Not Found [IP: 91.189.91.15 80] Failed to fetch http://security.ubuntu.com/ubuntu/pool/main/m/mysql-5.5/mysql-client-5.5_5.5.34-0ubuntu0.12.04.1_i386.deb  404  Not Found [IP: 91.189.91.15 80] Failed to fetch http://security.ubuntu.com/ubuntu/pool/main/m/mysql-5.5/mysql-client_5.5.34-0ubuntu0.12.04.1_all.deb  404  Not Found [IP: 91.189.91.15 80] E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?   What could be the issue here? How do I solve it?


Help I have inherited this old computer from my grandfather and I have no clue what the password is and without the password it will not update. does anybody know how to change the user password without the current pass or a way to find the current password? VER: 16.04 LTS OS: 64-Bit If you do have a answer can you make it in simple steps that a noob could understand... Thanks!

I'm working on a Ubuntu system, and my client has completely forgotten his administrative password. He doesn't even remember entering one; however it is there.  I've tried the suggestions on the website, and I have been unsuccessful in deleting the password so that I can download applets required for running some files. Is there a solution?


Please let me know how it can be possible to change url without page refreshing and without using hash tag.

How would I have a  action that may have some effects on the current page but would also change the URL in the browser so if the user hits reload or bookmark, then the new URL is used?    It would also be nice if the back button would reload the original URL.  I am trying to record JavaScript state in the URL.


I am trying to parse information with regex, that is laid out in a style similar to json. Part of the problem I am having doing this involved identifying pairs of curly brackets.   group = {     field = element     innergroup = {         field = element         field = element     }     field = element     innergroup = { field = element } }  array = { field = element }   The first step in solving this problem is to identify the inner groups, bracketed off material that has no curly brackets between them. In the above example:  innergroup = {     field = element     field = element } #and innergroup = { field = element } #and array = { field = element }   I have tried to find these inner groups by using a few different regex commands. This is the closest I got.  \{.*?\}   I know that it has something to do with the fact that the "." character means all characters except for line breaks. I also have to figure out a way to rule out characters that are either of the curly brackets.  [Update]  Previous questions have asked how to do this when the curly brackets are all on one line. However, this does not address this innergroup.  innergroup = {     field = element     field = element }   The other questions also don't take into account the fact that there are many curly brackets, and thus other regex functions will find things like.  group = {     field = element     innergroup = {         field = element         field = element     }   Any help is appreciated. Thanks.

Unfortunately, despite having tried to learn regex at least one time a year for as many years as I can remember, I always forget as I use them so infrequently. This year my new year's resolution is to not try and learn regex again - So this year to save me from tears I'll give it to Stack Overflow. (Last Christmas remix).  I want to pass in a string in this format {getThis}, and be returned the string getThis. Could anyone be of assistance in helping to stick to my new year's resolution?    Related questions on Stack Overflow:


The following SQL Server query need help       select      JI.id, RBIEnvironment from    (select         issue,        case when cfname='RBI-Environment'                then customvalue               else null         end as 'RBIEnvironment'      from X) as CT where      CT.issue = JI.id group by      JI.id, RBIEnvironment   The issue is the CT table returns the data in following format  1   NULL 1   STG 1   PROD 2   SIT 2   DIT 3   SIT   Hence the outer query returns   1   NULL 1   STG 1   PROD 2   SIT 2   DIT 3   SIT   I need in following format  1   STG,PROD 2   SIT,DIT 3   SIT   Please use the same inner dynamic table as such as it contains some more columns which needs to be displaye din the resultselt .This inner table is linked with the outer table using the issue field and ID field respectively

I've got two tables:  TableA ------ ID, Name  TableB ------ ID, SomeColumn, TableA_ID (FK for TableA)   The relationship is one row of TableA - many of TableB.  Now, I want to see a result like this:  ID     Name      SomeColumn  1.     ABC       X, Y, Z (these are three different rows) 2.     MNO       R, S   This won't work (multiple results in a subquery):  SELECT ID,        Name,         (SELECT SomeColumn FROM TableB WHERE F_ID=TableA.ID) FROM TableA   This is a trivial problem if I do the processing on the client side. But this will mean I will have to run X queries on every page, where X is the number of results of TableA.   Note that I can't simply do a GROUP BY or something similar, as it will return multiple results for rows of TableA.   I'm not sure if a UDF, utilizing COALESCE or something similar might work?


how can I clear complete package traces in ubuntu devices? I am trying to uninstall a package from golang binary. After uninstall when I do dpkg -l /apt-cache  still I am getting package name and configuration files information. Is it possible to remove those traces or uninstall the package using shell script by running script from package maintainer scripts?

I've searched the net for such information and found different command lines, like these ones:  sudo apt-get remove application sudo apt-get remove application*  sudo apt-get remove --purge application sudo apt-get remove --purge application*  sudo apt-get purge application sudo apt-get purge application*   So, what is the correct way? Is it necessary to use that "*"?  After that, I also found these commands:  sudo updatedb sudo locate application sudo rm -rf (file/folder name)


I do not have internet at home but I can go to an internet cafe to download things.  The thing is I have Ubuntu and I don't no how to download Ubuntu-compatible software  from another PC and then get it installed on my PC at home.  What do I need to do?

I have a friend who has got a computer that is not connected to the Internet. Is there any way to install software offline easily?


I kept receiving Full memory on the iphone so I changed the storage plan to 50 GB. It's been almost a week, I checked the payment, it's been succesfully done, yet the storage is not updated on the phone. Any idea what action should I take? Many thanks, Cristina

I just changed my storage plan for 50 GB for $0.99 per month. When i went on settings>General>Storage and icloud usage, where it said storage above it i didnt have more storage. But the second box, where it said icloud abov it had upgraded to 50 GB. But i dont have any more storage for me to be able to get more apps etc.


How do I avoid Post 11, Post 12" from 4th page of Pagination?   Total number of posts in my blog ( say 15 ) Maximum number of posts, I want to show ( say $max = 10) Posts per page should be 3 only.        $max = 10;      $items_per_page = 3;    $paged = ( get_query_var('paged') > 0 ) ? get_query_var('paged') : 1;      $query = new WP_Query( array( 'posts_per_page' => $items_per_page  , 'paged' => $paged ) );       if( $query->have_posts() ) {       while( $query->have_posts() ) {        $query->the_post();        the_title();       }      }       $total = ceil( $max / $items_per_page );  // 4     echo paginate_links( array( 'total' => $total ) );       wp_reset_postdata();      wp_reset_query();    output  Pagination  Page 1      : Post 1, Post 2, Post 3 Page 2      : Post 4, Post 5, Post 6 Page 3      : Post 7, Post 8, Post 9 Page 4      : Post 10, Post 11, Post 12 ==> should show only "Post 10"   Note  From my question, i want to show 10 posts only. paginate_links() generates 4 links. site.com/page/1/ = shows P1, P2, P3 site.com/page/2/ = shows P4, P5, P6 site.com/page/3/ = shows P7, P8, P9 site.com/page/4/ = shows P10, P11, P12 => Here i need to avoid P11, P12

How can I exclude one specific post from a WP_Query query? (For example, show all posts apart from a post with the ID 278)  I've tried the post__not_in argument but it just removes all posts..  Any help would be great.  Here is my current query  <?php     $temp = $wp_query;     $wp_query= null;     $wp_query = new WP_Query(array(         'post_type' => 'case-study',         'paged' => $paged,     ));     while ($wp_query->have_posts()) : $wp_query->the_post(); ?>   Thanks


We have a subtheme, mytheme that is based off of the classy base theme. We have set Aggregate CSS Files = true and when the pages load we end up with many aggregated CSS files.   One issue is that we don't need all the CSS for anonymous users, only authenticated users since most of them are for logged in users.   How would I only add the following CSS for only authenticated users, but not anonymous users using the mytheme.libraries.yml?  Goal:   We do not want to override anything in those libraries, but rather remove them all together from render based on if the user is authenticated or not.    CSS files included in local development:  <styles media="all"> @import url("/core/themes/classy/css/components/progress.css?pe4tq3"); @import url("/core/themes/classy/css/components/dialog.css?pe4tq3"); @import url("/core/themes/classy/css/components/action-links.css?pe4tq3"); @import url("/core/themes/classy/css/components/button.css?pe4tq3"); @import url("/core/themes/classy/css/components/collapse-processed.css?pe4tq3"); @import url("/core/themes/classy/css/components/container-inline.css?pe4tq3"); @import url("/core/themes/classy/css/components/details.css?pe4tq3"); @import url("/core/themes/classy/css/components/exposed-filters.css?pe4tq3"); @import url("/core/themes/classy/css/components/field.css?pe4tq3"); @import url("/core/themes/classy/css/components/form.css?pe4tq3"); @import url("/core/themes/classy/css/components/icons.css?pe4tq3"); @import url("/core/themes/classy/css/components/inline-form.css?pe4tq3"); @import url("/core/themes/classy/css/components/item-list.css?pe4tq3"); @import url("/core/themes/classy/css/components/link.css?pe4tq3"); @import url("/core/themes/classy/css/components/links.css?pe4tq3"); @import url("/core/themes/classy/css/components/more-link.css?pe4tq3"); @import url("/core/themes/classy/css/components/pager.css?pe4tq3"); @import url("/core/themes/classy/css/components/tabledrag.css?pe4tq3"); @import url("/core/themes/classy/css/components/tableselect.css?pe4tq3"); @import url("/core/themes/classy/css/components/tablesort.css?pe4tq3"); @import url("/core/themes/classy/css/components/textarea.css?pe4tq3"); @import url("/core/themes/classy/css/components/ui-dialog.css?pe4tq3"); @import url("/core/themes/classy/css/components/messages.css?pe4tq3"); </styles>   We initially thought to do the following in the mytheme.info.yml file, but that would mean we have to exclude every single CSS manually (line by line).  name: 'mytheme' type: theme base theme: classy package: custom core: 8.x libraries:   - mytheme/library1 stylesheets-remove:   - core/assets/vendor/normalize-css/normalize.css

I would like to remove all CSSs automatically included from stable theme:  /core/themes/stable/css/system/components/*   I can remove them one by one inside the .info.yml file:  stylesheets-remove:   - 'core/themes/stable/css/system/components/ajax-progress.module.css'   - 'core/themes/stable/css/system/components/autocomplete-loading.module.css'   - ...   Is there a way to remove all of them at once?   Something like:  stylesheets-remove:   - 'core/themes/stable/css/system/components/*'


Does Stack Exchange provide any option to be forgotten? Under  users have the right to be forgotten, but I'm unsure how this works legally with Stack Overflow.  What if I want to enact that right to have my account, and all content I have posted to any Stack Exchange website, deleted?  I wanted to do just that today, but I couldn't find anything on what rights I have as a user to have all my data completely removed.

If a citizen of EU would request all his questions and answers to be deleted from all Stack Exchange sites, would that request be carried out?  I'm not just talking about account deletion, where questions and answers by the user are being anonymized. I'm talking about the case where the user demands all his questions and answered be deleted.  Would Stack Exchange be doing something illegal if they refused the request?


My parents are applying for visitor visa to the UK. My father receives a monthly pension. This comes into my mother's and father's joint account. My mother has Fixed Deposits (FD) under her name. Including the pension and FDs, they have sufficient funds for the trip.   Can they enter the total amount from FDs and pension in each application form, or can only my mother enter income from FDs in her form as they are only in her name.   Also, is a letter needed stating that father has the permission to use the money from FDs for the trip?

The UK Visas and Immigration Directorate publishes  that provides helpful tips that can result in successful visa applications. Section 2 of this guidance opens is entitled "other documents you may want to provide" (emphasis mine).  Section 2: other documents you may want to provide – all visitors This section provides guidance on the types of documents that you may want to provide to help us consider your application against the Immigration Rules. Previous travel documents/passports, which show previous travel. Financial documents showing that you have sufficient funds available.  These must clearly show that you have access to the funds, such as:  bank statements building society book proof of earnings such as a letter from employer confirming employment details (start date of employment, salary, role, company contact details) where a third party (who is either in the UK or will be legally in the UK at the time of your visit) is providing financial support to you e.g. a business, a friend or a relative, documents to show that they have sufficient resources to support you in addition to themselves and any dependant family should be provided   The first item is "bank statements" and this ties in with the , which says...  evidence that you can support yourself during your trip, eg bank statements or payslips from the last 6 months  (Note 'eg' is a Latin abbreviation meaning "for example"; this appears to be optional rather than a fixed requirement.) Question: How should someone interpret this such that the chances of success are maximized? How many statements should I submit? What are they looking for and what do my bank statements tell about me?


I want to show that every element in the field of fractions of $K[[X]]$ can be written as $\sum_{k=-n}^\infty a_kX^k$ where $a_k\in K, n\in\mathbb{Z}$.  My first attempt was to rewrite  $\displaystyle \frac{\sum_{i=0}^\infty a_iX^i}{\sum_{j=0}^\infty b_jX^j}=\lim_{N\to \infty}\frac{\sum_{i=0}^N a_iX^i}{\sum_{j=0}^N b_jX^j}$  where I am not completely sure, if this is correct. I know that I can write an element of $R[[X]]$ where $R$ is a ring like this. Then I tried polynomial division and some similar things. Also I know that if $b_0$ would be not zero, I can invert the whole polynomial and arrive at the conclusion, even with $n=0$.   However, I was not able to progress from here.

Let $R$ a ring, and let $$\displaystyle R[[x]]=\left\{\sum_{k=0}^{\infty}a_k x^k\;\middle\vert\; a_k\in R\right\}$$ with addition and multiplication as defined for polynomials.  We have that $R[[x]]$ is a ring containing $R[x]$ as a subring.  How to prove that if $a_0\in R$ is a unit, then  $\displaystyle\sum_{k=0}^{\infty}a_k x^k$ is a unit in $R[[x]]$?


I really need some gold fast. I want to get the clan castle. I am at TH3 if you are wondering.

I want to know how to get gold faster in Clash of Clans, so I can upgrade my town hall to level 8.   I tried upgrading my mines but  it made no difference. I attacked people with 200k loot but it made no difference (it gets robbed).


I just flagged  as off topic.  I flagged it with the following reason, but I don't think this was quite the right reason for this question:     Questions concerning problems with code you've written must describe   the specific problem — and include valid code to reproduce it — in the   question itself. See SSCCE.org for guidance.   I'm pretty sure that reason doesn't make sense for that question, but since that question is way off topic, I don't know what reason I should have used. What reason should be used for way off topic questions?

I have less than 3000 rep on StackOverflow. Now that the new closing changes are live, I cannot supply a custom off topic message:    I can enter a custom off topic flag message without issue here on meta, though it only has three canned off topic reasons, rather than five.  I'm not sure if this is the same for users with enough rep to vote to close directly, but the lack of a custom message eliminates the ability to use the correct flag reason in some cases.  For example, I wanted to flag , which is simply off topic on SO. However, I can't use a custom message, and none of the canned ones are appropriate.    appears to be the most up to date official information on custom reasons, and indicates that they are remaining in play for now.  supports that.  If this is by design, how should I flag such questions? This is not a case worth bothering the mods over, so I don't want to use a custom diamond attention flag.


I tried today to install xubuntu on my PC but I had some problems in partitioning, while I was trying to fix it, I accidentally deleted everything from the partitions .  So is it possible to recover from ntfs with Xubuntu .  The data that was on my hard drive exceed 400GB of songs, family photos, my work !!

I am on Ubuntu 12.04 64-bits  I accidentally deleted a NTFS 255 GB partition using Gparted, and yes it contains LOTS of important data.  Upon realizing the deletion I haven't yet created any file-system on it. So it still shows Unallocated.    I tried Testdisk , but it shows entire partitions created from the beginning.  This sdb is my secondary drive with Xubuntu and Kubuntu on it. And that 255 GB NTFS  partition was cross platform storage drive.  I am currently in sda with Ubuntu and Win7 in dual boot, which enables me to use it as Safe recovery option rather then Live USB drive.   First ,  should i allocate it to ? file-System for better recovery .  Second , i really need to recover data from this drive so please give me possible  suggestions and proven methods of data recovery.  Third ,does Testdisk requires deleted partition to be allocated for its recovery .  I am currently trying the answer seen here  with Testdisk scanning for partition second time, hoping to recover it.   It looks a duplicate but i can't confirm if the OP got it right. Since my first doubt is to allocate it or not.  If any clarification required please do comment ,i will add it.  Edit: TestDisk deeper search results.      The following partitions can't be recovered:          Partition               Start        End    Size in sectors     >  HPFS - NTFS          22241 107 11 55592   3 27  535777280        FAT32 LBA            274460 158 19 460576 228 16 2989957948  NTFS, 274 GB / 255 GiB & for FAT32 LBA 1530 GB / 1425 GiB


I have installed ubuntu 16.04.6 LTS (32 bit) OS on Windows 10 (64 bit) OS using Bootable pendrive on my Lenevo laptop. I chose this option "Erase Windows 10 and install  Ubuntu" so it has been lead to  erase my perent Windows 10 OS as well as all data of hard disk and installed Ubuntu 16.04.6 LTS (32 bit) OS. I updated it from software update and get new update version 18.04.6 version.  So my problem is that how to get my back up data of Windows 10 OS? Does it possible to get back up data of windows OS using my current OS (Ubuntu 18.04.6 32 bit)?  Please guide me.

I have a Toshiba satellite A-200 laptop with a Vista OS on it with 4 NTFS partitions  (C:) Vista  (D:) Entertainment  (E:) Work  (F:) Sources   and I wanted to start using Ubuntu instead. So I tried it first from the live CD and everything was OK and all the partitions were shown and working and so I decided to install Ubuntu to replace Vista on the (C:) drive. After I did that I can no longer find my folders and files on the (D:), (E:), (F:) partitions and the only file system that is shown is one 198 GB although my HDD is 320 GB.  I can't access the lost data on the remaining 120 GB which I hope is still there and not totally lost  I am now working from the live CD but I am unable to install testdisk. Can I recover the Vista partitions by the product recovery CD to get my laptop back to the factory settings? Can I recover the NTFS partitions using a recovery program for Windows or will that make the problem worse?   I need these data badly as I don't have a backup for them.


Could you use these two sentences the same way? Which one is worse:  This wasn't no common day. This wasn't a common day.

Is "not unpleasant" a double negative, and hence bad grammar?  See the first answer (by Ham and Bacon) to , for the basis of this question:     "Did you enjoy the movie?"      "Well, I didn't not enjoy it, but..."   Are all "not un..." forms incorrect?  They are very widely used, much more so than the blatant "not not" or "didn't not", etc.


Hardware:     Thunderbolt to DisplayPort cable   The  unfortunately doesn't have any reliable information about supported resolutions in external monitors because of this:   I can currently run 3840x2160@60hz. I want to run 5120×1440@60hz, which is ~10% less pixels. Official spec says maximum is 2560x1600, which is literally half of my current resolution.   Since this type of monitor is quite new, I only see articles/videos using newer MacBooks.  Has anyone tried this yet or do you know how I could figure this out before actually buying the monitor?

How do I find out the number, type, resolution & refresh rate of additional monitors I can attach to my MacBook or MacBook Pro?  This is an attempt at a canonical QA, as per the Meta QA -   to try prevent the myriad "same but different" questions we get on every possible combination of computers, cable & monitors There are perfectly good resources out there that Ask Different should not have to duplicate the efforts of.


If I jump and stay in the air for a long enough time, will my position be changed since the Earth is rotating?

If I'm standing at the equator, jump, and land 1 second later, the  Earth does NOT move 1000mph (or .28 miles per second) relative to me,  since my velocity while jumping is also 1000mph.   However, the Earth is moving in a circle (albeit a very large one),  while I, while jumping, am moving in a straight line.   How much do I move relative to my starting point because of this? I  realize it will be a miniscule amount, and not noticeable in practise,  but I'd be interested in the theoretical answer.


I'm interested in equations like $y'(x) = y(x+1)$. Note that the argument of the function $y$ on the right hand side of that last equation is $x+1$. The right hand side does not contain a multiplication. We have a function $y$ that takes an argument $x$ which is written as $y(x)$. So the derivative of the solution is equal to the value of the solution "a little bit to the right". I do have an application for this, in case somebody would ask, but I'm interested most of all in the general theory instead of the specific instance (so no XY-problem; thanks Xander H.!).  I can't find the correct name for this kind of equations. Can somebody provide me a pointer?

We already solved or argued differential equations, integral equations and even function equations. But I encounter the following, which I call it "series equation":     Is there any nonzero function $f$ satisfying the series equation   $$f(x)=\sum_{n=0}^{\infty}\frac{f(n)}{n!}x^n \tag{*} $$   The source: I interested to solve the equation $$f'(x)=f(x+1)$$ and I found out $$f^{(n)}(x)=f(x+n)$$ thus: $f^{(n)}(0)=f(n)$ and if we consider  $f$ having a taylor series, then the expression $(*)$ will be the case.  But I have no idea how $f$ would be. Is such a function exists?  Thanks.


$$ \begin{align} x = 3\sec\theta, dx &= 3\sec\theta\tan\theta d\theta\\\\ \int \frac{dx}{\sqrt{x^2-9}} &= \int \frac{3\sec\theta\tan\theta d\theta}{\sqrt{(3\sec\theta)^2 - 3^2}} \\\\ & = \int \frac{3\sec\theta\tan\theta d\theta}{\sqrt{3^2(\sec^2\theta -1)}} \\\\ &= \int \frac{3\sec\theta\tan\theta d\theta}{\sqrt{3^2\tan^2\theta}} = \int \sec\theta\\\\ &= \ln|\sec\theta + \tan\theta| + C = \ln| \frac{x}{3} + \frac{\sqrt{x^2-9}}{3}| \end{align} $$  However, wolphram alpha says the answer is $\ln |x+ \sqrt{x^2-9}$  I am wondering how did it get rid of the 3 in the denominator? This is pretty much how I got my answer: $$ x = 3\sec\theta \\ \frac{x}{3} = \sec\theta \\ \frac{\sqrt{x^2-9}}{3} = \tan\theta $$

$$\int \frac{dx}{\sqrt{x^2 -9}}$$  $x = 3 \sec \theta \implies dx = 3 \sec\theta \tan\theta d\theta$  $$\begin{align} \int \frac{dx}{\sqrt{x^2 -9}} & = \frac{1}{3}\int \frac{3 \sec\theta \tan\theta d\theta}{\tan\theta} \\ \\ & = \int  \sec\theta d\theta \\ \\ & = \ln | \sec\theta + \tan\theta| + c\end{align}$$  $x = 3\sec \theta  \implies \sec\theta = \frac {x}{3}$  $\tan\theta = \frac{\sqrt{x^2 - 9}}{x}$  I have have confused x with 3 but I cannot get the proper answer which is  $$\ln | x +  \sqrt{x^2 - 9}| + c$$  I always get $\dfrac{x}{3}$ or $\dfrac{\sqrt{x^2 - 9}}{x}$ or some variation of that, I can't eliminate them to get their answer.


Can you help me prove that every planar graph can be expressed as a union of (maximum) five forests?  Ι used induction on the number of vertices. A planar graph $G$ has at most $3|V|-6$ edges, so there is at least one vertex $v$ of degree 5 or less.  Let $\{w_1,\ldots, w_j\}$; $j \le 5$ be $v$'s neighbors in $G$.  Then let $F_1,\ldots, F_5$ be the 5 edge-disjoint forests (some may be empty) such that $\cup_{j=1}^5 F_i = E(G \setminus \{v\})$. How do I prove that $F_1,\ldots, F_5$ exist?  Then for each $i \le j$ set $F'_i = F_i + \{v,w_i\}$, and (if $j$ is strictly less than 5) for each $i \in \{j+1,\ldots, 5\}$ set $F'_i=F_i$. Then each $F'_i$ is also a forest, and that each edge of $G$ is in one of the $F'_i$s.  Special thanks to user Mike for the answer.

How can I prove that every planar graph can be expressed as a union of (maximum) five edge-disjoint forests?  Only thing I can think about is going somehow like the $5$ color theorem but I get stuck in the middle. Or with induction, but still something doesn't fit. Can you help?


Einstein's happiest thought of his life led to so called acceleration-gravity equivalence by simply imagining a man free falling. This simple thought led Einstein to formulate his general theory of relativity. But I want to know how mathematically he came up with the conclusion such as gravity is interpreted as a curvature in the fabric Of space and time using this principle.

Einstein described his discovery of the equivalence principle as the "happiest thought of my life".  Why?  What, in broad conceptual terms, is the logical chain of reasoning that leads from the equivalence principle to general relativity?


I'm looking for a free hosting provider which provides an SSL Certificate at no additional charge. Does anyone know of a hosting provider which can provide such a service?   Thanks in advance,  Amani Swann

This is a "catch-all" question designed to serve as an answer for all questions about choosing web hosting.  Pro Webmasters no longer accepts new questions about how to choose hosting.  All future questions pertaining to finding web hosting should be closed as a duplicate of this question. For more information about this policy please see .    How to find web hosting that meets my requirements?  What we're looking for in answers to this question are the basics about web hosting:   What is web hosting? What is the difference between shared, VPS, and dedicated hosting? How does a content delivery network relate to web hosting? Anything else you feel is helpful in finding a web host.   What we do not want is:   Endorsements or recommendations for specific web hosts We do not want your experience or other subjective information (just the facts please)


I want insert some records in database, but something go wrong. When compile code, the console return java.lang.NullPointerException at line:  ps = connection.prepareStatement(insert);     public class SignUpController implements Initializable {      @FXML     private TextField fullname;      @FXML     private PasswordField email;      @FXML     private TextField password;      @FXML     private CheckBox check;      @FXML     private Button signup;      @FXML     private Button login;      private PreparedStatement ps;      @FXML     public void logIN(ActionEvent event) throws IOException {          login.getScene().getWindow().hide();         Stage login = new Stage();         Parent root = FXMLLoader.load(getClass().getResource("/FXML_Files/Login.fxml"));         Scene scene = new Scene(root);         login.setScene(scene);         login.show();     }      @FXML     public void signUP(ActionEvent event) throws SQLException {         ConnectionClass conToDB = new ConnectionClass();         Connection connection;         connection = conToDB.getConnection();         String insert = "INSERT INTO student(fullName, password, email) VALUES(?,?,?)";         ps = connection.prepareStatement(insert);          ps.setString(1, fullname.getText());         ps.setString(2, password.getText());         ps.setString(3, email.getText());          int i = ps.executeUpdate();         System.out.println("Data inserted");     } }     public class ConnectionClass extends Configs {  Connection con;  public Connection getConnection() throws SQLException{       try {       Class.forName("com.mysql.cj.jdbc.Driver");      String str = "jdbc:mysql://" + Configs.dbhost + ":" + Configs.dbport + "/" + Configs.dbname;      con = DriverManager.getConnection(str, Configs.dbuser, Configs.dbpass);      con.close();   } catch (ClassNotFoundException | SQLException ex) {       ex.getStackTrace();   }     return con; }

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


Suppose that  $\{a_n\}$ be a sequence of real numbers.let $\{n_{k}\}$ be an increasing sequence of positive integers, and let $A_{k} = a_{n_{k}} + a_{n_{k}+1}+ ... +a_{n_{k +1}-1}$, for each $k \in \mathbb{N}$. Prove that if $\sum_{n = 1}^{\infty} a_{n}$ converges, then  $\sum_{k = 1}^{\infty} A_{k}$ converges. Give an example to show that the converse is not true.  Can anyone explain for me in the term $a_{n_{k+1} -1}$ in the definition of $A_k$ we take a decreasing index (i.e why we subtract 1 and not add 1 to $n_{k+1}$ as we continued adding 1 to $n_{k}$ ) or this is a typo?  Also can anyone give me a numeric example for the direction we want to prove ?  Also I received a hint about the proof that I should use Cauchy criterion, could anyone provide me with a little bit more details in this direction?  Those are related links:  1-   2-  Thank you!

Let $\{a_n\}$ be a sequence of real number, let $\{n_k\}$ be an increasing sequence of positive integer and let $A_n=a_{n_k}+a_{n_{k+1}}+...+a_{n_{k+1}-1}$ for $k \in N$. Prove that if $\sum_{n=1}^\infty a_n$ converges then $\sum_{k=1}^\infty A_k$ converges. Is the converse true?  I know that $\sum_{n=1}^\infty a_n$ converges implies that $lim _{n_>\infty} a_n =0$, can I conclude that $A_n$ ->$0$ as well, even if I can conclude that, it still doesn't prove that $\sum_{k=1}^\infty A_k$ converges, am I correct?


I've read , but neither of the posts does seem to address my concerns. The problem is as follows:     Assuming a device that keeps something in a gravitational field on a constant height, like an electromagnet, how does one measure the required power?   I'm stumbling on that because the equation $P = Fv$ would mean that, assuming the object stays in place, the power is zero. That might be true for, say, a rigid construction holding something up. What if I am actively trying to keep something up, like holding it in my hand, or powering an electromagnet to create an electromagnetic field to keep something in the air? I am applying a constant force, but the object doesn't move!  I've tried to imagine it from the point of theoretical loss of potential energy I'm preventing, but it only got me to something like $P = g^2 m t$, which depends on time. In fact, every attempt to tackle the energy was in vain, because the velocity of the object in a gravitational field, if left without the support, wouldn't be constant (thus making the power depend on time), and is apparently not fit to describe the problem formally.

I read the definition of  as  $$W ~=~ \vec{F} \cdot \vec{d}$$  $$\text{ Work  =  (Force) $\cdot$ (Distance)}.$$ If a book is there on the table, no work is done as no distance is covered. If I hold up a book in my hand and my arm is stretched, if no work is being done, where is my energy going?


Have anyone ever had a problem with the yn560tx not connecting to the 560iii? It was working at one point of time and the night i used it, it just stopped firing the flashes. I have already tried resetting it to factory mode, changing the channels and groups but nothing has worked.

I have a Yongnuo YN-560 III and a pair of RF-603II (C3) triggers. I have a Canon Rebel T5i.   I put one trigger on the hot shoe.  When this trigger is in TX mode I get a blue comm light and I can fire a test flash using the large test button on the trigger. But when I press the shutter button to take a picture, there's no flash.  The trigger and flash are on Channel 1. The trigger on the hot shoe is set to TRX. TX is fine, TRX gives me no flash. The flash and camera are in M mode.  I don't have a trigger on the flash because the Mark III has a built-in trigger The problem seems to be the camera.  The trigger can talk to the flash but the camera is not sending a flash command through the trigger in the hot shoe to the flash.  Grateful for anything you could suggest.


Is it possible to play GTA Online on PS4 with my friends on PC?

Grand Theft Auto Online exists on five different platforms: XBox 360, PS3, XBox One, PS4, and PC. Do any of these play on the same servers, allowing people on differing platforms to play together?


This Electronics SE  includes a link to an example solution. The link entered in the text of the answer is   https://www.amazon.com/gp/product/B01G5SUZEG/   and is displayed like that as well.  But the link given to my browser is   https://rads.stackoverflow.com/amzn/click/B01G5SUZEG   I'm just curious what this is called, and if SO is able to generate revenue or other side benefits from clicks on this.

We have officially discontinued the Amazon book affiliate remnant ads, since despite our best efforts they don't perform well for our audience and cannot be made to perform well.  We've often wondered,   I'm thinking this isn't a problem; it has gotten lots of support historically. So we're going to go ahead and do it, so the company Amazon account is still getting some use, and we benefit a little.   To be clear: from this point on, all Amazon links posted on all sites will automatically be rewritten to add our affiliate link. We have a clever affiliate redirect that geolocates the IP address and redirects to the appropriate regional Amazon store (amazon.uk, amazon.ca, et cetera).  If you have any feedback on this, or suggestions, as they say … speak now or forever hold your peace!


I'm making a ww2 thing and I'm using Nazi weapons and I'm not sure if I have to ask the company to use them or if its ok to just add them without any problem. I really just wanna know if its ok because I've seen many other games add those types of weapons but I have heard of companies making agreements with gun manufacturers.

When creating your own model for a weapon, say the M4 carbine, and using the model in your game. Do you need a license to use it commercially? I know that racing games like GT5 has a license for each and every car, but the same apply for weapons?


Websites can ask permission to make themselves protocol handlers, which means that when you click on a link with a certain protocol, that link will be opened "using" that website.  How do I do this with Gmail for the mailto protocol?  I'm using Chrome, but I hope there is some setting in Gmail that I can toggle for this, so that I don't need to ask this for every browser I use.  I looked in the Chrome settings, and there is a way to manage protocol handlers, but not to add new ones. The option can be found under the privacy settings.

I noticed that when I open up Gmail on Google Chrome, a  asks me if I want to let Gmail be my "mailto:" handler.  If I select "No," I'm assuming that Gmail will no longer ask me to be a mailto: handler. But then let's say I change my mind and do want Gmail to handle mailto: links, how do I get the popup to appear again?


For a specific task I want to select a decent font. For that I want to compare the text “E G PM” for all my installed fonts (or even more) on a Linux system (Ubuntu in this case). Especially the bold face of a font (if it has any) will more likely match my requirements.  A quick visual viewing will probably sort 90% out already, so I was thinking of seeing a list of my string in the different font faces available on my system.  The font viewers/managers I tried are not up for the task. Which app could help me here or how can I quickly solve my problem otherwise?  The apps I tried are:   fontmatrix   version 0.6.0+svn20110930 (0.9.99) a bug hinders your configured text to be shown (font name is always shown) it does not show the bold face of a font in the list (just regular)  gnome-specimen   you have to add each font face individually (2-3 clicks) to seem them you see substituted fonts (if glyph is not in font) without being warned/told  fontypython crashes at startup on this Ubuntu bionic system fontmanager.app is unusable in i3 window manager  gwaterfall   text is fixed to “Lazy dog...” needs each font selected individually (4 clicks at least)  font-manager   has a great browse mode, but in that mode it doesn’t show your own text (only font name)  gnome-font-viewer can’t set text typecatcher   custom text, yes shows just regular type face for each font (i.e. not bold or others) requires 1 click to see the font doesn’t show system fonts(?), only a big selection of downloadables  Opcion   horrible user interface doesn’t show bold type face (and others) in the list  FontViewer   makes fonts look ugly (doesn’t antialias or whatnot) no list, no bold face  kfontview   doesn’t find system fonts itself (select font with “Open...” on a font file) doesn’t do lists of fonts

I want to view the fonts that are installed on my system. Specifically, I want the client-side (fontconfig) fonts, not the old-style X11 bitmap fonts on the server (for which xfontsel does an adequate job). I guess what I'm looking for would be called a font viewer or font gallery. I want to see a bit of sample text for each font, ideally configurable sample text.  Being able to filter by font name, available character sets and other characteristics would be a plus.  A search of packages in Debian wheezy found gnome-font-viewer and kfontview, but they can only display a single font. I'd rather avoid depending on software that isn't widely available, including on the current Debian stable and Ubuntu LTS.


Here is a simple way to show and hide a dropdown menu when an element (flag, in this case) is clicked:   function handleDropDown(elementId) {   const element = document.getElementById('languages');   if (element.style.display === "block") {     element.style.display = "none";   } else {     element.style.display = "block";   } } .flag-icon-wrapper {   margin-right: 20px;   padding-top: 5px; }  .flex {   display: flex; }  .flag-icon {   width: 50px; }  .is-hidden-initially {   display: none; }  .languages-menu {   border: 1px solid black; }

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    Now I want to hide the menu when you click anywhere else on the screen. The menu should hide when you click anywhere outside of it. Without jQuery. I found a comment on the top answer for , which explains how to do it with Vanilla JS:   let menu = document.getElementById('languages'); let nav = document.getElementsByClassName('languages-menu'); let html = document.body.parentNode;  function handleDropDown(elementId) {   const element = document.getElementById('languages');   if (element.style.display === "block") {     element.style.display = "none";   } else {     element.style.display = "block";   }   menu.addEventListener('click', toggleClassMenu);     html.addEventListener('click', function(event) {   event.preventDefault();   if (menu.contains(event.target)) {     element.style.display = "none";   } else {     element.style.display = "block";   } }); } .flag-icon-wrapper {   margin-right: 20px;   padding-top: 5px; }  .flex {   display: flex; }  .flag-icon {   width: 50px; }  .is-hidden-initially {   display: none; }  .languages-menu {   border: 1px solid black; }

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    But as you can see it creates a TypeError: "Uncaught TypeError: document.getElementByID is not a function" - I'm not sure why that's causing a type error (?) getElementById should be camel case, correct? And besides the error, are there any other suggestions for doing this only in JavaScript?

I have some HTML menus, which I show completely when a user clicks on the head of these menus. I would like to hide these elements when the user clicks outside the menus' area.  Is something like this possible with jQuery?  $("#menuscontainer").clickOutsideThisElement(function() {     // Hide the menus });


Definitions:         Let $A$ be an $n\times n$ matrix. The $n\times n$ matrix $B(=A^{-1})$ is an inverse for $A$ if $AB=BA=I$.   Let $A$ be a $k\times n$ matrix.The $n\times k$ matrix $B$ is a right inverse for $A$ if $AB=I$.The $n\times k$ matrix $C$ is a right inverse for $A$ if $CA=I$.   Here $I$ is  identity matrix of appropriate order.      Now,      Theorem 2: For any square matrix $A$, the following statements are equivalent:         $A$ has inverse.   $A$ has a right inverse.   $A$ has a left inverse.      I know that      Theorem 1: If $A$ has a right inverse $B$ and a left inverse $C$, then $A$ is invertible and $B=C=A^{-1}$.   Proof: $C=CI=C(AB)=(CA)B=IB=B.$   But I can't prove Theorem 2 .

If $A$ and $B$ are square matrices such that $AB = I$, where $I$ is the identity matrix, show that $BA = I$.    I do not understand anything more than the following.   Elementary row operations. Linear dependence. Row reduced forms and their relations with the original matrix.   If the entries of the matrix are not from a mathematical structure which supports commutativity, what can we say about this problem?  P.S.: Please avoid using the transpose and/or inverse of a matrix.


The  says, when use /Z7:     Produces an .obj file containing full symbolic debugging information   for use with the debugger. The symbolic debugging information includes   the names and types of variables, as well as functions and line   numbers. No .pdb file is produced.   Because obj files will be link into exe file finally. So I think the debug info will write into the final building file (exe file).  In , MSDN says:     It is not possible to create an .exe or .dll that contains debug   information. Debug information is always placed in a .pdb file.   After I test it, I found:   whatever /Z7 or /Zi was set, PDB file always get generated.  build with /Z7, and generate a core dump file, use vs open this core dump file, it still need a PDB file to debug.   It seems first msdn doc I refer is outdated.  Can I debugging windows core dump file like linux app which only need a single core dump file? without any additional files like a PDB? Or this is an mission impossible.

Background  There are several different  you can use with the Visual Studio C++ compiler. They are:   (none)   Create no debugging information Faster compilation times  /Z7   Produce full-symbolic debugging information in the .obj files using CodeView format  /Zi       Produce full-symbolic debugging information in a .pdb file for the target using Program Database format.  Enables support for minimal rebuilds (/Gm) which can reduce the time needed for recompilation.  /ZI       Produce debugging information like /Zi except with support for Edit-and-Continue    Issues   The /Gm flag is incompatible with the  (Visual Studio 2005/2008) If you want to enable minimal rebuilds, then the /Zi flag is necessary over the /Z7 flag. If you are going to use the /MP flag, there is seemingly no difference between /Z7 and /Zi looking at MSDN. However, the  states that you must use /Z7 to support parallel builds.   Questions   What are the implications of using /Zi vs /Z7 in a Visual Studio C++ project?  Are there other pros or cons for either of these options that I have missed?  Specifically, what is the benefit of a single Program Database format (PDB) file for the target vs multiple CodeView format (.obj) files for each source?   References


When I open a new terminal, it doesn't execute auto-start my bash_profile. I need to do "source .bash_profile".   When I use Screen, it happens again.

I have a user, say user1, which has modifications to its .bash_profile, one of them changing the PATH, e.g.: export PATH=/some/place:$PATH. This change works fine if I log on as user1 or do a su - user1.  But if I try to run a command via su as root, e.g.:  su -c test.sh oracle   (test contains echo $PATH)  It doesn't seem to have the modified PATH (or root's PATH, for that matter). I've also tried copying .bash_profile to .profile, to no avail.   Why is this happening?


I'm reading "Friendly Introduction to Number Theory". Now I'm working on Primitive Pythagorean Triples Exercises 2.1 (a) on P18.      We showed that in any primitive Pythagorean triple $(a, b, c)$, either $a$ or $b$ is even. Use the same sort of argument to show that either $a$ or $b$ must be a multiple of 3.   (1) $a^2 + b^2 = c^2$ with a odd, b even, a,b,c having no common factors  (2) $a^2 = c^2 - b^2 = (c-b)(c+b)$  (3) $c + b = s^2$ and $c - b = t^2$  (4) $c = \frac{(s^2 + t^2)}{2}$ and $b = \frac{(s^2 - t^2)}{2}$  (5) $a = \sqrt{(c-b)(c+b)} = st$  (6) $a = st$, $b = \frac{(s^2 - t^2)}{2}$, $c = \frac{(s^2 + t^2)}{2}$    I have no idea how I start doing this. Can you give me a hint? I think I need to show that both the following (1) and (2) are satisfied.  $X \neq 0$  (1) $a\equiv 0\pmod 3$ and $b\equiv X\pmod 3$  (2) $b\equiv 0\pmod 3$ and $a\equiv X\pmod 3$

Prove that for any primitive Pythagorean triple (a, b, c), exactly one of a and b must be a multiple of 3, and c cannot be a multiple of 3.  My attempt:  Let a and b be relatively prime positive integers.  If $a\equiv \pm1 \pmod{3}$ and $b\equiv \pm1 \pmod{3}$,   $c^2=a^2+b^2\equiv 1+1\equiv 2 \pmod{3}$  This is impossible as the only quadratic residues modulo 3 are 0 and 1.  So far, so good.  If one of a, b is $\equiv 0 \pmod{3}$ and the other is $\equiv \pm1 \pmod{3}$,  $c^2=a^2+b^2\equiv 0+1\equiv 1 \pmod{3}$  This is the part I don't understand. Just because $c^2\equiv 1\pmod{3}$ doesn't mean that $c^2$ must be a perfect square. For example, $a=12$ and $b=13$ satisfy the above conditions but $c^2=a^2+b^2=313$, which isn't a perfect square.


Is it possible to draw open circuits using circuitikz like these below?    Thank you.

I'd like to include an oscilloscope symbol in my circuitikz diagram, like this:    I looked around, and it doesn't seem like there is one built in. Is it possible to get something like this into circuitikz?


My husband is non-EU , but holding a Uk residence permit card without bearing or written in Resident Card  as member of EEA family member. Can he still travel with me in Italy ?

Most of the already posted questions were about traveling between EU countries. In my case I would like to visit Austria with my South African wife. We got married over 20 years ago in Austria, lived there together for 6 years, but moved to SA 16 years ago. The permanent residence my wife had once expired and she needs a Schengen visa. The Austrian Embassy tells me that my wife has to apply in person, show proof of income, proof of accommodation, has a travel insurance and all fulfills all other requirements like every ordinary applicant.  Is the Directive 2004/38/EC only applicable for spouses when they are already within the EU or is it also valid in our case?   In particular the personal appearance is a problem as we are living in the Southern Cape and going to the embassy means a round trip of 2600 km, closer is the consulate in Cape Town but still requires a 1200 tour.


I am trying to create a discord bot. It works great but i have a small problem. I save some values into the database. Some sentences. Now if a specific condition is met then it prints everything on the discord chat. The problem here is that discord has a limit of 2000 letters per message so if the returned text has more than 200 characters, i get an error. I experimented a bit and i figured out that if i print the sentences on 10s bulks, it is enough to get my whole text. So i have something like that: if len(options) > 0:    await context.channel.send("Text at the start:\n")    newBlock = []     for count, element in enumerate(options, 1):      newBlock.append(options[count])      if count % 10 == 0:        myArrayAsText = '\n - '.join([i for i in newBlock])        await context.channel.send("```fix\n - " + myArrayAsText + "```")        newBlock = []  The problem here is that if the last occurance doesnt have a dividable number to 10, it will not printed until the condition is met. if count % 10 == 0: How can i best print 10 entries at a time even if the count is not dividable to 10? Best regards

I have a list of arbitrary length, and I need to split it up into equal size chunks and operate on it. There are some obvious ways to do this, like keeping a counter and two lists, and when the second list fills up, add it to the first list and empty the second list for the next round of data, but this is potentially extremely expensive.  I was wondering if anyone had a good solution to this for lists of any length, e.g. using generators.  I was looking for something useful in itertools but I couldn't find anything obviously useful. Might've missed it, though.  Related question:


We are Israeli citizens residing in the US on work visas. Our daughter is a citizen of both the US and Israel. We are travelling from the US to Israel and back soon. Since our daughter is a dual-citizen she needs an Israeli passport to enter/exit Israel and a US passport to enter/exit the US.  Should we expect any issues if her US passport expires in less than 6 months at the time of travel?

As a dual citizen, my US passport will expire one day after traveling to the US (May 4th). I will be staying for one week, flying back to Europe afterwards (where I am a resident). Can I enter with my US passport, and leave with my valid EU passport? I'm flying with Icelandair.  Also, in this case I shouldn't try to get an ESTA for my EU passport, right?  PS. When trying to use an emergency procedure to renew my US passport, I am not getting any replies from the US consulate.


I need help in proving the following.  Given $Q$ a polynomial evaluated over the complex numbers such that $\alpha_1, ..., \alpha_n$ are roots of $Q$ and $P$ a polynomial such that $\deg P<n$ prove that $$ \frac{P(z)}{Q(z)}=\sum_{k=1}^{n}\frac{P(\alpha_k)}{Q'(z)(z-\alpha_k)} $$ At first I tried kind of 'brute forcing' from one side and then the other and I think I got farther when beginning with the right side but still I didn't manage to get the identity. Any help is appreciated.

Here, $Q$ is a polynomial with distinct roots $\alpha_1, \ldots, \alpha_n$ and $P$ is a polynomial of degree $<n$. Once again, the task is to show  $$\frac{P(z)}{Q(z)} = \sum_{k=1}^{n}\frac{P(\alpha_k)}{Q'(\alpha_k)(z-\alpha_k)}$$  For reference, this is page 32 exercise 2 in Complex Analysis by Ahlfors. I'm having a ton of trouble making connections between what is presented in the text and this problem. The section is on rational functions and is incredibly concise. There was never a mention of derivatives and their relationships to rational functions, so I'm guessing here that it just means that $Q'(a_k)$ is a polynomial of degree $n-1$.  I don't even know where to start here, but I do have a couple question which might motivate the proof. What does $P(\alpha_k)$ mean? I don't see what a root of $Q$ has to do with a completely different polynomial. What is the relationship between the roots of $Q$ and the roots of $Q'$? And finally, where does the derivative of $Q$ come in?


$F(x,y) =x^2 y /x^2+y^2 , (0,0) $. The answer is that F is  not continues at $(0,0)$ because    $\lim (x,y)>(0,0) ~ f(x,y)$ does not exist  $(0,0) \in D_f$   where $D_f$ is the domain of $f$.  I try a method where you let $y=g_1(x)=x$ And $y=g_2(x)=x^2$ which is it to curves that pass the point $(0,0)$ etc  And the limit is equal which means that the function is exist !   And why does point $(0,0)$ belong to $D_f$ ?

How would you prove or disprove that the function given by $$f(x,y) = \begin{cases} \dfrac{x^2y}{x^2 + y^2} & (x,y) \neq (0,0) \\ 0 & (x,y) = (0,0) \end{cases}$$ is continuous at $(0,0$)?


I have 6GB ram and my system is Ubuntu 14 & 32 bit. How can I use the ram more than 4GB? please help me.

I have a Toshiba A100, which I upgraded to 4 GB of RAM. The hardware startup indeed shows 4 GB of RAM, and I recently installed Windows 7, just to see how it behaves on it. So far so good, it displays 4 GB of RAM. Not that I tried to use it all, but it displays it. Previously under XP, I also would see 4 GB of RAM.  But under Ubuntu 9.10 (32 or 64 bits), it only displays 2.9 GB of RAM. And my kernel is the "pae" compiled one, which is supposed to do the trick to work around the 32-bit CPU limitation.   How can I get Ubuntu to fully use my 4 GB of RAM?