7I was trying to install Spotify on my fresh install of Ubuntu 16.04 LTS 64Bits, something went wrong, now I got the error message shown in the picture and cannot open the update manager.    These are the steps that I followed:   Add the Spotify repository signing key to be able to verify downloaded packages  sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys BBEBDCB318AD50EC6865090613B00F1FD2C19886  Add the Spotify repository  echo deb http://repository.spotify.com stable non-free | sudo tee /etc/apt/sources.list.d/spotify.list  Update list of available packages  sudo apt-get update  Install Spotify  sudo apt-get install spotify-client    This is the message shown in the terminal  $ sudo apt update N: Omitiendo fichero «sp» del directorio «/etc/apt/sources.list.d/», ya que no tiene extensión de nombre de fichero E: Tipo «sudo» desconocido en la línea 1 de la lista de fuentes /etc/apt/sources.list.d/spotify.list E: No se pudieron leer las listas de fuentes.

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


I am just shifted from windows to ubuntu 20.04 LTS. when I try to install flux gui in ubuntu it throws error like E: Unable to locate package xflux .I run following three command in terminal one by one . sudo add-apt-repository ppa:nathan-renniewaldock/flux sudo apt-get update sudo apt-get install fluxgui  But it shows following error after running above three commands: E: Unable to locate package fluxgui Now, I don't know how to solve it.Do you have any solution or new way to install f.lux in ubuntu 20.04 LTS. Please help me. Thank you!

When updating, I get the following error message:   W: The repository 'http://ppa.launchpad.net/mc3man/trusty-media/ubuntu xenial Release' does not have a Release file.   Here, I find another statement on this error:   This recommends removing certain PPAs; and, I'm not sure if I should do that since it might mean not getting the updates that I need.    Is this what I should do?


Suppose $f(x+y)=f(x)+f(y)$ for some $f: R \rightarrow R$ such that $f$ is continuous at $0$.Show that $f(x)=\alpha x$ for some $\alpha \in R$. Hint: show that $f(nx) = nf(x)$, then show $f$ is continuous on $R$. Then show that $f(x)/x = f(1)$ for all rational $x$.   How can I show $f(nx)=nf(x)$?? I am stuck with the first hint, so I can't show any attempt.  Thank you in advance!

Assume $f$ is a function over $\mathbb{R}$ satisfying $f(x+y) = f(x)+f(y)$ for all $x,y \in \mathbb{R}$. Show that if $f$ is continuous, then $f(x) = cx$ for all $x \in \mathbb{R}.$   I find it hard to use the definition of continuity to derive anything from the equation. I think we could write the definition of the limit in terms to get $$\forall \epsilon,\exists \delta \quad 0<|x-a|<\delta \quad \implies \quad |f(x)-L| < \epsilon.$$ I am not sure where to go from here.


Have a push/pull faucet for our upstairs bathtub/shower, and it recently started leaking behind the shower wall and onto the ceiling below.   It appears to only leak when the faucet isn't pushed completely closed. Any idea how I can fix this? See images below.

My shower leaks when water is splashed onto the trim plate around the water dial.  I assume there is some sort of gasket that needs to be replaced.  I do not know what any of these parts are called.  Please enlighten me as to the name of the parts I'll be dealing with, and any information that may be helpful in fixing this problem.  To be clear, I can run the shower for a solid hour when nobody is in there with no leaking.  Once someone splashes water onto the handle or spigot, water can be seen leaking around the pipe (witnessed through access panel).


Today I came across a scenario wherein an assignment was done inside a finally block, a similar code snippet as below     public static void main(String[] abc) {     System.out.println("Returned \t"+ testFinally()); }  public static int testFinally() {     int aVariable =2;     try {         System.out.println("value of aVariable inside try \t"+aVariable);         return aVariable;     } finally {         aVariable = 100;         System.out.println("value of aVariable inside finally \t"+aVariable);     } }  The output was bit strange to me  value of aVariable inside try     2 value of aVariable inside finally     100 Returned  2  Then I tried the same with StringBuffer and String  With StringBuffer      public static StringBuffer testFinallyStringBuffer() {     StringBuffer strBuffer = new StringBuffer("ABCD");     try {         System.out.println("value of strBuffer inside try \t"+strBuffer);         return strBuffer;     } finally {         strBuffer.append("EFGN");         System.out.println("value of strBuffer inside finally \t"+strBuffer);     } }  Output  value of strBuffer inside try     ABCD value of strBuffer inside finally     ABCDEFGN Returned  ABCDEFGN  Output was as expected.  With String      public static String testFinallyString() {     String str = "ABCD";     try {         System.out.println("value of str inside try \t"+str);         return str;     } finally {         str = str + "EFGN";         System.out.println("value of str inside finally \t"+str);     } }  Output  value of str inside try   ABCD value of str inside finally   ABCDEFGN Returned  ABCD  From this behavior, it seems as if variable(primitive/immutable objects/mutable objects) was passed from try block to finally block like parameters are passed to a method. Although, use of finally block is to do clean-up activities.But I want to know if my understanding is correct or there is something more to it.  Update  Though, I could not found anything satisfactory from the  Question with which this Question has been marked DUPLICATE with. However, there are few comments claiming that the evaluation of Return statement happens only once. Having said that, Still variables are local scope. Any change made to them should be visible on accessing these later on. Possibly, RETURN internally creates a copy of variable being returned(right before invocation of finally and actually returning to calling method) which is why primitive variable and immutable objects behaves different from mutable objects in this case.

Considering this code, can I be absolutely sure that the finally block always executes, no matter what something() is?  try {       something();       return success;   }   catch (Exception e) {        return failure;   }   finally {       System.out.println("I don't know if this will get printed out"); }


I wonder why Eevee renders slowly when pressing F12, while viewport rendering does the same exact picture (down to the pixel) but takes less than a second. Where are these seconds lost ? What kind of computation is the CPU-GPU doing that makes me wait to finally display the same picture as "viewport render" ? It's annoying because I would like to use the compositor (not compatible with viewport rendering) while keeping fast render times (for a still image, 1 second vs 15 is not an issue, but for animations it's more a problem).

Viewing a 3d object is considered rendering. Hence, why is there even a "Render Image" option, and why is it so slow on my computer? --Edit-- Not sure why no one understands the question. Whenever you rotate your 3D model around, that's considered rendering. Hence by that logic the "Render Image" button is worthless.


I don't even know how to properly word this, but I'll try my best to explain it in code:  typedef void( *ExampleFn )( PVOID p1, PVOID p2, PVOID p3 );  struct Example {     void ExampleFunction( PVOID p1, PVOID p2, PVOID p3 )     {         // do something with Example's members     } };  Example example; ExampleFn exampleFn = example.ExampleFunction;   So, I get this error:  Error C2440 '=': cannot convert from 'void (__thiscall Example::* )(PVOID,PVOID,PVOID)' to 'ExampleFn'   I understand the problem, Example::ExampleFunction is a __thiscall and ExampleFn is not, but how can I go about this?  How to have a Example object with a ExampleFn-like function in it that can use that object's members?

I'm using an API that requires me to pass a function pointer as a callback. I'm trying to use this API from my class but I'm getting compilation errors.   Here is what I did from my constructor:  m_cRedundencyManager->Init(this->RedundencyManagerCallBack);   This doesn't compile - I get the following error:      Error  8 error C3867: 'CLoggersInfra::RedundencyManagerCallBack': function call missing argument list; use '&CLoggersInfra::RedundencyManagerCallBack' to create a pointer to member   I tried the suggestion to use &CLoggersInfra::RedundencyManagerCallBack - didn't work for me.   Any suggestions/explanation for this??  I'm using VS2008.  Thanks!!


I have this very often that I quickly want to test something (html, css or javascript), so I create a small test file like this:  <doctype html>  <html>     <head>         <style>         </style>         <script>         </script>     <head>      <body>     </body> <html>   I'm using VIM, and I was wondering if it is possible to add something somewhere, with the result that VIM can generate this template for me?

I have recently started using Vim as my text editor and am currently working on my own customizations.  I suppose keyboard mappings can do pretty much anything, but for the time being I'm using them as a sort of snippets facility almost exclusively.  So, for example, if I type def{TAB} (:imap def{TAB} def ():<ESC>3ha), it expands to:  def |(): # '|' represents the caret   This works as expected, but I find it annoying when Vim waits for a full command while I'm typing a word containing "def" and am not interested in expanding it.   Is there a way to avoid this or use this function more effectively to this end? Is any other Vim feature better suited for this?     After taking a quick look at , it looks like it's the best option and much easier to customize than I first thought.  To continue with the previous example:  :Snippet def <{}>():   Once defined, you can expand your snippet by typing def{TAB}.


I'm Egyptian and I have Bosnian tourist visa, if I travel by Austrian airlines Cairo-Vienna-Sarajevo and back by Lufthansa Sarajevo-Munich-Cairo do I need transit or any kind of visa for Vienna and Munich?

I found many related questions on this site but I am still not sure about the rules. How can I decide if I need a visa to transit? Schengen members as of May 2021 are as follows:  Austria Belgium Czech Republic Denmark (excluding Greenland and the Faroe Islands - but an open border with the Schengen Area is maintained) Estonia Finland France (excluding overseas departments and collectivities) Germany Greece Hungary Iceland Italy Latvia Liechtenstein Lithuania Luxembourg Malta Netherlands (excluding Aruba, Curaçao, Sint Maarten and the Caribbean Netherlands) Norway (excluding Svalbard) Poland Portugal Slovakia Slovenia Spain (except Ceuta and Melilla) Sweden Switzerland


I share an office with a co-worker and wanted to write something about the office that she and I share. Should I do something like one of these:   Stacey's and I's office Stacey and I's office   ?

I just stumbled upon a :     My wife and I's seafood collaboration dinner. How does it look?   Sure enough, the top comment immediately points out that it should be "my wife's and my". However, a cross-post to the Grammar subreddit produced :     It's fine as it is written. "my wife and I" is a noun phrase, functioning as a subjective pronoun in the singular and made possessive with the apostrophe. It is exactly the same as "our".      It seems weird because you would never use "I's" on its own but it is not on its own here - it is part of a noun phrase.   That's a rather intriguing argument. Does it hold any water?


so I have to convert infix to postfix with the example, ab/(c-a)+de. My code did not show any errors only some warnings, it compiled but there is no output. When I run it will show me the message below. Exception in thread "main" java.lang.NullPointerException     at LinkedStackTest$Convert.convertToPostfix(LinkedStackTest.java:40)     at LinkedStackTest$Convert.main(LinkedStackTest.java:60)  I tried looking over the code multiple times and still do not know what I did wrong. Any help or advice would be great thanks! My code: public class LinkedStackTest {     static class Convert     {         static int getPriority(char ch)         {             switch (ch)             {                 case '+':                 case '-':                     return 1;                 case '*':                 case '/':                     return 2;             }             return -1;         }          public static String convertToPostfix(String infix)         {             LinkedStack<Character> linkStack = new LinkedStack<>();             String postfix = "";              for (int i = 0; i < infix.length(); i++)             {                 char ch = infix.charAt(i);                  if (Character.isLetterOrDigit(ch)) {                     postfix += ch;                 } else if (ch == '(') {                     linkStack.push(ch);                 } else if (ch == ')') {                     while (linkStack.peek() != '(') {                         postfix += linkStack.peek();                         linkStack.pop();                     }                 } else {                     while (!linkStack.isEmpty() && getPriority(ch) <= getPriority(linkStack.peek())) {                         if (linkStack.peek() == '(')                             return "Invalid";                         postfix += linkStack.peek();                     }                     linkStack.push(ch);                 }             }             while (!linkStack.isEmpty())             {                 if(linkStack.peek() == '(')                     return "Invalid Expression";                 postfix += linkStack.pop();             }             return postfix;         }          public static void main(String[] args) throws Exception         {             String infix = "a*b/(c-a)+d*e";             String postfix = convertToPostfix(infix);             System.out.println("Infix: " + infix);             System.out.println("Postfix: " + postfix);         }     } }

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


I have a home partition from a previous installation that I grew out of (zorin os, really slow boot time) and now I have a kubuntu install that I just recently created. My question is: How do I both transfer the packages from the previous installation (all applications) and use the users from the old home for the new installation? In the past, simply mounting the partition as home has not created the new users, it has simply created a new user during install, and when I've tried creating a second user, deleting the home folder of that user and putting a shortcut to the other folder renamed to the same name, it has not gotten past the logon screen for that user. Is there something that I'm missing here?

I have 2 HDD drives in my computer. At the moment second drive is mounted as /media/storage.  How can I move my user data from /home to /media/storage/home?  Can I just move the data over there and then simply symlink it back?


I have been trying to detect anomalies in my time-series dataset. What I am trying to accomplish is the following: I have a multivariate dataset, where two columns are of special interest. One tells us the maximum power that should have generated and the other column tells us the actual power generated. What I am trying to do is label a datapoint as "fault" or "fault-free". I am trying to do it through a difference between theoretical maximum and the real power generated. Plotting difference demonstrates that distribution is skewed (see picture).   Most of the methods I have read about, including PCA/Mahal. distance/Neural Nets ask for normal (or fault-free) training dataset, which I cannot provide with certainty. I have also tried control charts but that didn't work.  Are there any methods that you can recommend?  Thank you

Under a classical definition of an outlier as a data point outide the 1.5* IQR from the upper or lower quartile, there is an assumption of a non-skewed distribution. For skewed distributions (Exponential, Poisson, Geometric, etc) is the best way to detect an outlier by analyzing a transform of the original function?  For example, distributions loosely governed by an exponential distribution, could be transformed with a log function - at which point is it acceptable to look for outliers based on the same IQR definition?


I've just installed ubuntu 14 and setted my password but when i'm trying to install other software and ubuntu ask me to enter my password, it's always wrong even though i'm sure it's the right password. that's also happen when i logout and try to login again

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?


If I run ubuntu on a flash stick as the instructions say, then install it, where does it install to?  I have windows 10 and windows 7 on two different disks on a Asus computer with 16 GB memory, and want to run ubuntu on a different drive but not mess up the boot manager by installing it on one of the two disks internally. Someone explain the process of how to run ubuntu on a flash stick without messing up the boot manager on the uefi bios .

If you are hurrying to reply, System → Administration → StartUp Disk Creator -- no, that's not what I'm talking about.   I want to try Ubuntu 11.04's Unity without touching my existing Ubuntu install.  To do this, I need to install the nVidia drivers first (sigh).  To do this, I need changes to persist a reboot.  To do this, I need to really install Ubuntu on a USB key.  How do you do that?    What I tried   I tried to make a USB key from , then boot from it, then choose "Install Ubuntu." The installer refused to install to the installation media itself. I tried, from my installed copy of Ubuntu:  sudo kvm /dev/sdb --cdrom .cache/testdrive/iso/ubuntu_natty-desktop-i386.iso   ...but the installer didn't detect the disk properly.


I can't get past the : apt install linux-headers-$(uname -r) Reading package lists... Done Building dependency tree        Reading state information... Done E: Unable to locate package linux-headers-4.18.0-kali2-amd64 E: Couldn't find any package by glob 'linux-headers-4.18.0-kali2-amd64' E: Couldn't find any package by regex 'linux-headers-4.18.0-kali2-amd64'  I checked my sources.list which contains: deb http://http.kali.org/kali kali-rolling main contrib non-free deb-src http://http.kali.org/kali kali-rolling main contrib non-free  uname -r returns: 4.18.0-kali2-amd64  And when I run apt-cache search linux-image I get: linux-headers-4.18.0-kali3-amd64 - Header files for Linux 4.18.0-kali3-amd64 linux-headers-4.18.0-kali3-cloud-amd64 - Header files for Linux 4.18.0-kali3-cloud-amd64 linux-headers-4.18.0-kali3-rt-amd64 - Header files for Linux 4.18.0-kali3-rt-amd64 linux-image-4.18.0-kali3-amd64 - Linux 4.18 for 64-bit PCs linux-image-4.18.0-kali3-amd64-dbg - Debug symbols for linux-image-4.18.0-kali3-amd64 linux-image-4.18.0-kali3-cloud-amd64 - Linux 4.18 for x86-64 cloud linux-image-4.18.0-kali3-cloud-amd64-dbg - Debug symbols for linux-image-4.18.0-kali3-cloud-amd64 linux-image-4.18.0-kali3-rt-amd64 - Linux 4.18 for 64-bit PCs, PREEMPT_RT linux-image-4.18.0-kali3-rt-amd64-dbg - Debug symbols for linux-image-4.18.0-kali3-rt-amd64 linux-image-amd64 - Linux for 64-bit PCs (meta-package) linux-image-amd64-dbg - Debugging symbols for Linux amd64 configuration (meta-package) linux-image-cloud-amd64 - Linux for x86-64 cloud (meta-package) linux-image-cloud-amd64-dbg - Debugging symbols for Linux cloud-amd64 configuration (meta-package) linux-image-rt-amd64 - Linux for 64-bit PCs (meta-package), PREEMPT_RT linux-image-rt-amd64-dbg - Debugging symbols for Linux rt-amd64 configuration (meta-package) linux-image-4.18.0-kali2-amd64 - Linux 4.18 for 64-bit PCs  I'm running kali on an external SSD with live persistence. I did update and upgrade.

I am trying to install Linux headers for Kali Linux on my machine and I have tried every possible solution on the internet but it always show "Unable to locate packages "  root@kali:/usr/sbin# apt-get install linux-headers-4.6.0-kali1-amd64 Reading package lists... Done Building dependency tree        Reading state information... Done E: Unable to locate package linux-headers-4.6.0-kali1-amd64 E: Couldn't find any package by glob 'linux-headers-4.6.0-kali1-amd64' E: Couldn't find any package by regex 'linux-headers-4.6.0-kali1-amd64'   Here is my sources.list file :  # Regular Repositories deb http://http.kali.org/kali sana main non-free contrib deb http://security.kali.org/kali-security sana/updates main contrib non-free # Source repositories deb-src http://http.kali.org/kali sana main non-free contrib deb-src http://security.kali.org/kali-security sana/updates main contrib non-free   Uname -a output :   root@kali:/usr/sbin# uname -a Linux kali 4.6.0-kali1-amd64 #1 SMP Debian 4.6.4-1kali1 (2016-07-21) x86_64 GNU/Linux


How can I show that the ideal $(x_1,x_2,x_3,...)$ (with infinitely many variables) in the ring $K[x_1,x_2,x_3,...]$ is not finitely generated.   I cannot complete the arguments as I thought if the ideal is generated by finitely many polynomials say $f_1,f_2,........f_n$ then these polys will contain only finitely many variables. Let  $x_k$ be the variable with highest subscript which will be involved in $f_i 's$. So $x_{k+1}$ will not appear in any of the $f_i's$. My target is to show that $x_{k+1}$ cannot be written as $K[x_1,x_2,x_3,.....]$ linear combination of $f_i's$. If possible suppose $x_{k+1}$=$g_1.f_1 +g_2.f_2+.........+g_n.f_n$. I am trying by putting $x_1=x_2=...=x_k$=$1$ but then I can't argue further. I want this to be completed in this way. Help me. Thank You.

Let $K$ be a field and $A=K[x_1,x_2,x_3,...]$. Prove that the ideal $I:=\langle x_i: i \in \mathbb N\rangle$ is not finitely generated as $A$-module.   I have no idea what can I do here, I mean, suppose $I$ is finitely generated, then there is a subset $S \subset I$ with $S=\{x_{i_1},...,x_{i_n}\}$ such that $\langle\{x_{i_1},...,x_{i_n}\}\rangle=I$. How can I arrive to a contradiction? Any suggestions would be appreciated.


I know that in order for a metric space to be complete, all Cauchy sequences in the metric space should converge to points in the space, and I also know the definition of Cauchy sequences. But I am struggeling to prove the above question. The only idea coming to my mind is to find a Cauchy sequence that doesn't converge in the metric space and thus I can prove that the metric space is incomplete.

Consider $C([0, 1])$, the linear space of continuous complex-valued functions on the interval $[0, 1]$, with the norm  $$\displaystyle\lVert f\rVert_1 = \int_0^1 \lvert f(x)\rvert \,dx.$$  I have to show that $C([0, 1])$ is not complete with respect to this norm. I have found the following example from a book.  Let $f_n \in C[0,1]$ be given by  $$f_n(x) := \begin{cases}  0   & \text{if $0 \le x \le \frac1{2}$}\\  n(x-\frac{1}{2}) & \text{if $\frac {1}{2} < x \le \frac {1}{2} + \frac {1}{n}$}\\  1              & \text{if $ \frac {1}{2} + \frac {1}{n} <x \leq 1 $} \end{cases}$$  How to prove that $f_n$  is a Cauchy sequence with respect to $\lVert \cdot\rVert_1$?   If I use basic definition then I have to prove that $\lVert f_n - f_m\rVert_1 < \epsilon$ $\forall n, m > N$. But I am finding it difficult to prove this.  Please help me to understand how to prove that $f_n$ is Cauchy sequence in $C([0, 1])$.  Thanks


this year I finished off my course of Physics I (the first general physics) at my university and we had a lot of exercises to do where in order to complete them I had to change the system coordinates, for example, from Cartesian to polar coordinates. But the book that I was using didn't have any theory explaining how to change coordinates and I had to use my intuition to solve it. Anyway, can you recommend any material (books, videos, etc) about coordinate changes in basic physics?  Also, is there any other books for basic physics that you guys recommend? I was using Halliday but it's so superficial and Morin was so complicated, I couldn't find any intermediary level book.   Ps: I'm asking for this content because even though I had good grades in the subject I don't think I've learned some stuff properly.

Every once in a while, we get a question asking for a book or other educational reference on a particular topic at a particular level. This is a meta-question that collects all those links together. If you're looking for book recommendations, this is probably the place to start.  All the questions linked below, as well as others which deal with more specialized books, can be found under the tag  (formerly ).  If you have a question to add, please edit it in. However, make sure of a few things first:   The question should be tagged  It should be of the form "What are good books to learn/study [subject] at [level]?" It shouldn't duplicate a topic and level that's already on the list   Related Meta:


I have recently installed Win 10 Pro. No matter how many times i try to disable Defender Antivirus with Group Policy Editor (Computer Configuration > Administrative Templates > Windows Components > Microsoft Defender Antivirus) by activating the policy "Turn off Windows Defender Antivirus" and clicking OK, Windows just ignores all my attempts and revert it back on like nothing happened... It just turns Turn off Windows Defender Antivirus from enabled back to Not configured When i close gpedit and open it back again i can see it's back to Not configured Tamper Protection is off ... I've been using PC's for 25 years without Antiviruses by using only common sense and Process Explorer. Why is Microsoft forcing me to use something i don't want on my own computer?

I have Windows 10 ver 2004. Since Windows Defender changed to Microsoft Defender Antivirus I'm unable to turn it off. In Local Group Policy (gpedit.msc) under Computer Configuration/Administrative Templates/Windows Components/Microsoft Defender Antivirus there is a key "Turn off Microsoft Defender Antivirus". Every time I check "enable" and log out or reboot the key is back to "Not configured". How to keep it disabled permanently, and therefore turn off Microsoft Defender Antivirus essentially?  (source: )


I'm asking mostly in relation to the forces acting on a person, but it would also be nice to know if there would be any impact on muscle strength, similar to when an astronaut goes into space.

Let's take a planet identical to Earth, but with rotation speed multiplied by ten thousand. What would happen with the gravity if it was spinning madly around itself? Would the centrifugal force make objects seem lighter than on normal Earth? Would the people on that planet be able to jump higher?


After restarting Ubuntu due to the pc crashing, I randomly see this:  The entire desktop is covered in icons. I cannot see them in the Desktop folder, nor move them around. Here is the output of cat ~/.config/user-dirs.dirs > xander@xander:~$ cat ~/.config/user-dirs.dirs > # This file is written by xdg-user-dirs-update > # If you want to change or add directories, just edit the line you're > # interested in. All local changes will be retained on the next run. > # Format is XDG_xxx_DIR="$HOME/yyy", where yyy is a shell-escaped > # homedir-relative path, or XDG_xxx_DIR="/yyy", where /yyy is an > # absolute path. No other format is supported. > #  XDG_DESKTOP_DIR="$HOME/" XDG_DOWNLOAD_DIR="$HOME/Downloads" XDG_TEMPLATES_DIR="$HOME/Templates" XDG_PUBLICSHARE_DIR="$HOME/Public" > XDG_DOCUMENTS_DIR="$HOME/Documents" XDG_MUSIC_DIR="$HOME/Music" > XDG_PICTURES_DIR="$HOME/Pictures" XDG_VIDEOS_DIR="$HOME/Videos"  Is this a bug? What can I do? I have this system:

As of now, my desktop has begun showing the contents of my home folder (~) instead of the contents of ~/desktop. I must have changed something, but I have no idea what, or what I was doing exactly when it happened.  How do I re-point gnome to the right folder?  I'm running Ubuntu 11.04.


Please help me . I am interested to learn linux. Can I install linux in any Laptop ❔ My laptop asus x556u Am I able to install linux ?

I am a bit financially strapped and received a Gateway GT5056 tower. The tower has an AMD dual core 64-bit processor in it. Will Ubuntu 12.04 run on this machine? I will not have any other application other than LibreOffice installed.


Suppose I have a function:  def f():   ...   ...   ...   return a,b,c   and I want to get only b in output of the function. Which assignment I have to use?  Thanks.

Say I have a Python function that returns multiple values in a tuple:  def func():     return 1, 2   Is there a nice way to ignore one of the results rather than just assigning to a temporary variable? Say if I was only interested in the first value, is there a better way than this:  x, temp = func()


If $f$ belongs to $C[-\pi, \pi]$  &  $\int_{-\pi}^{\pi}\ x^nf(x) =0$     for all non negative integer n. Then $f$ will be identically $0$.  How to do it by stone-weierstrass theorem?  Can anyone help me?

Let $f:[0,1]\to \mathbb{R}$ continuous, such that  $\forall n \in \mathbb{N},\int_0^1 f x^n dx=0$, show that $f\equiv 0$.  I think I should use Stone-Weierstrass Theorem and the Bernstein Polynomials, but I failed in my attempt of using, because the coefficients change at each power you choose. Is there any other way to do it, or someone that could help me with this method?


I don't understand the context in which you'd ever want a linked list over something like an arraylist.  In an arraylist, random access and appends are amortized constant time, inserts and deletes are linear time.  Linked lists, appends and prepends are also constant time (assuming you have pointers to head and tail) as well as inserts and deletes but only once you have the right element -- otherwise things like random access takes linear time.  Why would we ever want the latter? It sounds like inserts and deletes are constant time but only after you spend linear time to find the right element from which to insert or delete.  Is it only preferable if you're doing a lot of appends / deletes from a single spot so it's fast once you find the right one? But then why can't I do the same thing with an arraylist by shifting everything over by k spots and then filling in the inserts? Faster if the remaining size of the array is smaller than the first portion if it had been an arraylist you had to a an through linearly.

I've always been one to simply use:  List<String> names = new ArrayList<>();   I use the interface as the type name for portability, so that when I ask questions such as these I can rework my code.    When should  be used over  and vice-versa?


I have the following code:  If Sheets("EstimateTemplate").Visible Then     Sheets("EstimateTemplate").Select     ActiveWindow.SelectedSheets.Visible = False     Sheets("Navigation").Select Else     Sheets("EstimateTemplate").Visible = True     Sheets("Navigation").Select End If   how can I wrap it with "IF SHEET EXISTS" clause  I tried the following which didn't work  IF not Sheets("EstimateTemplate") = "" then    If Sheets("EstimateTemplate").Visible Then    Sheets("EstimateTemplate").Select    ActiveWindow.SelectedSheets.Visible = False    Sheets("Navigation").Select    Else    Sheets("EstimateTemplate").Visible = True    Sheets("Navigation").Select    End If end if

I have the following code that's not working as expected:  If Sheets("a") <> "" Then MsgBox ("sheet a exists")   How can I tell if sheet a exists in the workbook?


I'm on Windows 8.1 and I'm having a strange problem with my home network (I'm connected via ethernet to an Sitecom ADSL+ router).   Since yesterday morning, it's very difficult to reach every Google website (Google Search, Google News, YouTube, Blogspot, ...), while I can browse every other website, from Facebook to the most hidden website of the net (well, not literally).  If I try to open Google.com, most of the times (like 9 over 10) the browser stays on the "waiting for google.com" status.  Browsers   Tested on IE11, Firefox, Chrome. Same results. Tried to wipe all the caches, cookies and so on Tried to reset all the browser's settings to default   Network   ping google.com returns "good" results! (ping works with latency around 60ms) Tried to change the DNS, from the default given by my ISP to Google's and also OpenDNS. Nothing changes. Tried to flush the DNS cache with ipconfig /flushdns Tried to reboot the router (but I have not reset the configuration yet) I'm on IPv6 (10/10 on test-ipv6.com)   PC and other devices   All the PCs in this network have the same issue Instead, my mobile phone (that uses a totally different network) can browser Google and every other website without problems (so...well... Google works!).   What could be the cause? Could it be an ISP fault?  EDIT: This is a tracert google.com test:  C:\Users\Alessandro>tracert google.com  Traccia instradamento verso google.com [2a00:1450:4002:803::1003] su un massimo di 30 punti di passaggio:    1    <1 ms    <1 ms    <1 ms  2a01:2000:2001:fb07:66d1:a3ff:fe07:de81   2     *        *        *     Richiesta scaduta.   3    58 ms    60 ms    60 ms  2a01:20f0:2005::4   4     *        *        *     Richiesta scaduta.   5     *        *        *     Richiesta scaduta.   6     *        *        *     Richiesta scaduta.   7    63 ms    70 ms    71 ms  ibs-resid.milano30.mil.seabone.net [2001:41a8:20 :2::5]   8     *        *        *     Richiesta scaduta.   9    77 ms    78 ms    78 ms  2001:4860:1:1:0:1a6a:0:18  10    66 ms    63 ms    64 ms  2001:4860::1:0:458d  11    64 ms    63 ms    63 ms  2001:4860:0:1::207  12    66 ms    63 ms    62 ms  mil02s05-in-x03.1e100.net [2a00:1450:4002:803::1 003]  Traccia completata.

I'm  getting timeout errors on google-related sites. If I try to open google.com, gmail.com, etc, it will keep displaying the "waiting reply" on the browser bottom, and the page won't open. If I am browsing another site that includes, say, www.google-analytics.com, ajax.googleapis.com, google fonts, etc, then it start loading, displaying a "connecting to [google-related site]" on the browser bottom, and stall at that point for a long time.  I can browse other sites fine and they load quickly. I can ping the domains with 0% loss and <100ms times. I can ping 8.8.8.8, I am not behind a proxy, there is nothing on my hosts file, I am not at work or in a networked environment: it is a home network behind a router. I connect using wifi (I am too distant to use wired).   Other users on the same network don't have the issue. I can both ping and browse the sites. I have pinged ajax.googleapis.com from my android and my other laptop, and they return the same IP than on this laptop. They also share the same external IP address, according to   The issue happens on ubuntu 12.04, and as it is cyclic but not frequent enough to make sure, I don't honestly remember if it happens on Windows 7 as well (it is a dual-boot machine). Rebooting the router won't help. Rebooting the computer fixes the problem, until it happens again.  It's been happening for a few months now. The last time it happened (earlier today) I performed a ping before and after the reboot. Here's the results:  before  $ping ajax.googleapis.com PING googleapis.l.google.com (74.125.21.95) 56(84) bytes of data. 64 bytes from yv-in-f95.1e100.net (74.125.21.95): icmp_req=1 ttl=47 time=157 ms 64 bytes from yv-in-f95.1e100.net (74.125.21.95): icmp_req=2 ttl=47 time=163 ms 64 bytes from yv-in-f95.1e100.net (74.125.21.95): icmp_req=3 ttl=47 time=156 ms 64 bytes from yv-in-f95.1e100.net (74.125.21.95): icmp_req=4 ttl=47 time=165 ms 64 bytes from yv-in-f95.1e100.net (74.125.21.95): icmp_req=5 ttl=47 time=157 ms 64 bytes from yv-in-f95.1e100.net (74.125.21.95): icmp_req=6 ttl=47 time=155 ms 64 bytes from yv-in-f95.1e100.net (74.125.21.95): icmp_req=7 ttl=47 time=159 ms 64 bytes from yv-in-f95.1e100.net (74.125.21.95): icmp_req=8 ttl=47 time=157 ms   after  $ping ajax.googleapis.com PING googleapis.l.google.com (74.125.134.95) 56(84) bytes of data. 64 bytes from gg-in-f95.1e100.net (74.125.134.95): icmp_req=1 ttl=47 time=207 ms 64 bytes from gg-in-f95.1e100.net (74.125.134.95): icmp_req=2 ttl=47 time=154 ms 64 bytes from gg-in-f95.1e100.net (74.125.134.95): icmp_req=3 ttl=47 time=154 ms 64 bytes from gg-in-f95.1e100.net (74.125.134.95): icmp_req=4 ttl=47 time=152 ms 64 bytes from gg-in-f95.1e100.net (74.125.134.95): icmp_req=5 ttl=47 time=157 ms 64 bytes from gg-in-f95.1e100.net (74.125.134.95): icmp_req=6 ttl=47 time=160 ms 64 bytes from gg-in-f95.1e100.net (74.125.134.95): icmp_req=7 ttl=47 time=154 ms 64 bytes from gg-in-f95.1e100.net (74.125.134.95): icmp_req=8 ttl=47 time=157 ms 64 bytes from gg-in-f95.1e100.net (74.125.134.95): icmp_req=10 ttl=47 time=154 ms 64 bytes from gg-in-f95.1e100.net (74.125.134.95): icmp_req=11 ttl=47 time=152 ms   The issue happens on different browsers, I installed epiphany and it shows the same behaviour.  I have inspected the network tab on firefox and it shows a single, unreplied GET request:   I installed wireshark and listened for HTTP GET requests; on other sites it pops up on the report, but on ajax.googleapis it shows nothing. I listened then for DNS requests, there are some differences:     If connect via telnet to the port 80 of a random site and perform a GET it works, but I can't telnet to ajax.googleapis.com (or it's IP), the connection never completes.


I have a program which I have used for many years which manages the printing of text files according to control statements within the text file.    For instance, it will print headings at the top of each page, change lines per inch, change characters per inch, set margins, change from portrait to landscape, etc.  It does this by writing control strings directly to the printer, addressing the printer as LPT1, LPT2, or LPT3.    Now I need to use it to address a printer connected to a USB port, but I don't know how to address it.    Printer properties tell me that the printer is connected to port "DOT4_001", but when I attempt to write to that port, it simply creates a file in the current directory with that name and does not write to the printer.  Similarly, I cannot figure out how to write to that printer from a DOS window with the simple command "type file.txt >xxxx", although substituting "LPT1:" for "xxxx" works with a printer connected to a parallel port.   So my question is "How do I directly address a printer which is connected to a USB port?"

I have some legacy software that only prints on printers connected via an LPT port. The machine I need to use, however, doesn't have a parallel port. Plus my printer is a USB device.  How do I trick my computer into thinking my usb printer is hooked up to the lpt port?  Further, this is for an office. I'll have admin rights when implementing the work around, but I'm shooting for a solution that works while a 'regular' user is logged after everything is set up.


I've been given a series of points equidistant from one another, where each point can be raised (incremented) by a maximum value of a common constant c (each point can be incremented anywhere from 0 to c units) in order to help flatten the curve of the graph of these points as much as possible. I was wondering if anyone could help point me in the right direction as to what kind of formulas or functions would help flatten the curve as much as possible given the conditions above. I believe this is an optimization problem but I could be wrong and I would greatly appreciate a nudge in the right direction. (I believe I am trying to optimize for the flattest possible slope between each point) For example, Given the initial list of 10 equidistant points [75, 110, 115, 105, 95, 85, 75, 65, 45, 50] where each point can be incremented anywhere from 0 <= c <= 6, return a new list of 10 equidistant points where the slope between each point in the graph has been minimized by adding a c value to any/all of the points in the initial list. This is not school related so there is no need to solve the above problem if you don't want to. Any explanation as to how I may get a result is greatly appreciated.

Suppose we have a list of values, $L = (x_1, x_2, ..., x_n)$, and another list of numbers, $Q = (q_1, q_2, ..., q_n), q_i$ being the maximum value we can subtract from $x_i$ (so from $x_i$ we can subtract any number in $[0; q_i]$. I want to find a combination of subtractions such that the standard deviation of the resulting list will be minimal. (In other words, I want to find a set of values, $R = (r_1, r_2, ..., r_n)$, $r_i \in [0; q_i]$ such that the standard deviation of $L' = (x_1-r_1, x_2-r_2, ..., x_n-r_n)$ is minimal.) A graphical example (the blue points are the plotted $x_i$):  Any help would be appreciated. Thanks.


I am using the format function in SOQL to format a date to DD/MM/YYYY when retrieved.  I can see the formattedCreatedDate in the debug logs and it is displaying correctly but cant reference it in a VF page. Not sure why?  My SOQL is:  consultancyOpps = [Select Id, Name, CreatedDate,FORMAT(CreatedDate) formattedCreatedDate from Opportunity where RecordType.Name = 'Consultancy ORDER BY CreatedDate DESC];   My VF page is trying to fetch {!consultancyOpps.formattedCreatedDate} but I get an error. I can display the other fields fine (Id, Name).  Not sure what I need to do to be able to display the formattedCreatedDate

Apparently if I want to format a date to my own format ie. 1 June 2016 10:44 am I can only do this with outputText but output text does not respect the users time zone so everything is GMT. If I use outputField it automatically converts it to the users time zone but I have no control over the format it displays it in. Does someone know how to get my custom format to display in the users time zone? I don't care which I use I just want to show it my way in the proper time zone  This respects users time zone but I cannot control formatting  <apex:outputField value="{!c.CreatedDate}"/>   or This does not respect users time zone but I can control formatting   <apex:outputText value="{0,date,dd MMM YYYY h:mm a}">   <apex:param value="{c.CreatedDate}"/> </apex:outputText>   This method is called from the controller when page is called and populates the variable csComments with records  public void ShowComments() {   disp = true;   RetrieveAcctInfo();   caseNo = System.currentPagereference().getParameters().get('cn');   System.debug('Case No: ' + caseNo);   cd = [select id, AccountId, Priority from Case where CaseNumber=:caseNo];   if (acctid != cd.AccountId) { disp = false; errMsg = 'Access Restricted'; }    else {     csComments = [select Comment__c, CreatedDate from CSPComments__c where CaseCom__c=:cd.id ORDER BY CreatedDate DESC];     ccCount = csComments.size();   }   initpri = new List<SelectOption>();     initpri.add(new SelectOption('None',' -- Select Priority --', true));   initpri.add(new SelectOption('Level 1','1 - System Down'));   initpri.add(new SelectOption('Level 2','2 - Funtioning with Errors'));   initpri.add(new SelectOption('Level 3','3 - System Issue'));   initpri.add(new SelectOption('Level 4','4 - Non Critical Issue'));   inpri = cd.Priority;   curpri = inpri; }   This is the part of the page that is showing the results. The manager wants my date to be in the approved style of 1 June 2016 11:26 am    <apex:pageBlock id="cl" rendered="{!disp}">

Date/Time	Comment
       <apex:repeat value="{!csComments}" var="c">
                                       <apex:outputField value="{!c.CreatedDate}" />             	           <textarea class="dtarea" rows="4" cols="60" disabled="true">{!c.Comment__c}</textarea>
     </apex:repeat>
     </apex:pageBlock>


How is possible to populate lists, of fixed length, using all possible permutations of one or all elements of a list?  For instance, I want to populate lists of 3 elements containing all possible permutations of one or all numbers [1,2,3]. All ways of creating lists of length 3, with these 3 numbers, are:  arranging = [[1,1,1], [1,1,2], [1,2,2], [2,2,2], [1,1,3], [1,2,3], [2,2,3], [1,3,3], [2,3,3], [3,3,3]]  To find the possible permutations of each one of this lists I would use:  populating = [set(itertools.permutations(i, 3)) for i in arranging]  Which is equal to:  populating == [{(1, 1, 1)}, {(1, 2, 1), (2, 1, 1), (1, 1, 2)}, {(1, 2, 2), (2, 2, 1), (2, 1, 2)}, {(2, 2, 2)}, {(1, 1, 3), (1, 3, 1), (3, 1, 1)}, {(3, 1, 2), (1, 3, 2), (3, 2, 1), (2, 3, 1), (1, 2, 3), (2, 1, 3)}, {(2, 2, 3), (3, 2, 2), (2, 3, 2)}, {(3, 1, 3), (3, 3, 1), (1, 3, 3)}, {(3, 2, 3), (2, 3, 3), (3, 3, 2)}, {(3, 3, 3)}]  How would you create the list arranging (sorry for the terrible name)? Is there any other better solution?

How do you generate all the permutations of a list in Python, independently of the type of elements in that list?  For example:  permutations([]) []  permutations([1]) [1]  permutations([1, 2]) [1, 2] [2, 1]  permutations([1, 2, 3]) [1, 2, 3] [1, 3, 2] [2, 1, 3] [2, 3, 1] [3, 1, 2] [3, 2, 1]


In the Mail application, when I choose the option "see more from " the app unfolds the replied messages in different colors as quoted texts. How can we undo the unfolding and hide the quoted text? It is so messy right now.  Please see the image below for the part that I want to hide.

In Mail's conversation view, by default, quoted text is hidden and can be shown by clicking "See More from XXX" in the bottom of each message. After clicking that, how can quoted text be hidden again?


I am currently using a Mac running el Capitan but have now built my very first computer. I intend to use Ubuntu 16.04 as my OS.   My question is what i need to do in order to create a bootable USB, using my current OS, with which i can boot my new computer.   The internet is a vast place and the question has surely been asked before but i have not managed to find any answers. I'd be very thankful for any help.

I'd like to create an Ubuntu live USB stick on a Mac to use to install Ubuntu on another machine. How do I accomplish this?


Let $E$ be a finite dimensional $k$-vector space ($k$ may be assumed algebraically closed if needed) and $u,v \in \mathcal L(E)$ be two endomorphisms that commute ($u\circ v=v \circ  u$).  Does there exist a third endomorphism $w$ and two polynomials $P,Q\in k[X]$ such that $u=P(w)$ and $v=Q(w)$?  I think the heart of the problem is to deal with the nilpotent subcase (where u and v are supposed to be both nilpotent). If $u$ (or $v$) is cyclic (ie only one Jordan block) this is classical, but I am not sure how to deal with the general case...

Consider square matrices over a field $K$. I don't think additional assumptions about $K$ like algebraically closed or characteristic $0$ are pertinent, but feel free to make them for comfort. For any such matrix $A$, the set $K[A]$ of polynomials in $A$ is a commutative subalgebra of $M_n(K)$; the question is whether for any pair of commuting matrices $X,Y$ at least one such commutative subalgebra can be found that contains both $X$ and $Y$.  I was asking myself this in connection with frequently recurring requests to completely characterise commuting pairs of matrices, like . While providing a useful characterisation seems impossible, a positive anwer to the current question would at least provide some answer.  Note that in many rather likely situations one can in fact take $A$ to be one of the matrices $X,Y$, for instance when one of the matrices , or more generally if its  (so coincides with the characteristic polynomial). However this is not always possible, as can be easily seen for instance for diagonal matrices $X=\operatorname{diag}(0,0,1)$ and $Y=\operatorname{diag}(0,1,1)$. However in that case both will be polynomials in $A=\operatorname{diag}(x,y,z)$ for any distinct values $x,y,z$ (then $K[A]$ consists of all diagonal matrices); although in the example in  the matrices are not both diagonalisable, an appropriate $A$ can be found there as well.   I thought for some time that any maximal commutative subalgebra of $M_n(K)$ was of the form $K[A]$ (which would imply a positive answer) for some $A$ with minimal polynomial of degree$~n$, and that a positive answer to my question was in fact instrumental in proving this. However I was wrong on both counts: there exist (for $n\geq 4$) commutative subalgebras of dimension${}>n$ (whereas $\dim_KK[A]\leq n$ for all $A\in M_n(K)$) as shown in , and I was forced to correct  in the light of this; however it seems (at least in the cases I looked at) that many (all?) pairs of matrices $X,Y$ in such a subalgebra still admit a matrix $A$ (which in general is not in the subalgebra) such that $X,Y\in K[A]$. This indicates that a positive answer to my question would not contradict the existence of such large commutative subalgebras: it would just mean that to obtain a maximal dimensional subalgebra containing $X,Y$ one should in general avoid throwing in an $A$ with $X,Y\in K[A]$. I do think these large subalgebras easily show that my question but for three commuting matrices has a negative answer.  Finally I note that  to the cited MO question mentions a result by Gerstenhaber that the dimension of the subalgebra generated two commuting matrices in $M_n(K)$ cannot exceed$~n$. This unfortunately does not settle my question (if $X,Y$ would generate a subalgebra of dimension${}>n$, it would have proved a negative answer); it just might be that the mentioned result is true because of the existence of $A$ (I don't have access to a proof right now, but given the formulation it seems unlikely that it was done this way).  OK, I've tried to build up the suspense. Honesty demands that I say that I do know the answer to my question, since a colleague of mine provided a convincing one. I will however not give this answer right away, but post it once there has been some time for gathering answers here; who knows somebody will prove a different answer than the one I have (heaven forbid), or at least give the same answer with a different justification.


Is it possible to switch a certain Stack Exchange site's interface (as a personal preference) to the theme used by beta sites?  Some sites have flashy decorations or unreadable fonts (I prefer to disable antialiasing on fonts). It would be nice to have an option to see a site with the "beta" theme.  If there's a solution using custom styles, I would accept that as an answer.

edit please let me emphasize that I don't request additional themes but merely the ability to apply the already existing design of another SE site, e.g. to make  look like .    I really like the current themes of SOFU, and I love   but also  sounds plausible. So, what about the possibility to have a per-user setting of which theme to use for which site (maybe throwing in some bonus themes when Jin has the time)?


My site got hit ddos several times till now, i found that ddos traffic generally comes from linux os ... then, i wonder how to block linux users / traffic from accessing a site with htaccess?? Please advice..

This is a  about DoS and DDoS mitigation.   I found a massive traffic spike on a website that I host today; I am getting thousands of connections a second and I see I'm using all 100Mbps of my available bandwidth.  Nobody can access my site because all the requests time out, and I can't even log into the server because SSH times out too!  This has happened a couple times before, and each time it's lasted a couple hours and gone away on its own.  Occasionally, my website has another distinct but related problem: my server's load average (which is usually around .25) rockets up to 20 or more and nobody can access my site just the same as the other case.  It also goes away after a few hours.  Restarting my server doesn't help; what can I do to make my site accessible again, and what is happening?  Relatedly, I found once that for a day or two, every time I started my service, it got a connection from a particular IP address and then crashed.  As soon as I started it up again, this happened again and it crashed again.  How is that similar, and what can I do about it?


Let $A$ be the ring of continuous functions from $\mathbb{R}$ to $\mathbb{R}$ and let $I_c$ denote the functions that vanish at some fixed $c\in\mathbb{R}$. Is $I_c$ a maximal ideal? Give an example of a proper non-zero ideal of $A$ that is not of the form $I_c$ for some $c\in\mathbb{R}$.  My attempt: I think $I_c$ is not maximal, because we can consider the ideal $I_{c,d}$ of functions that vanish at fixed $c,d\in\mathbb{R}$. $I_c$ is clearly contained in $I_{c,d}$, but $I_{c,d}\neq A$ because $f(x)=1$ is not in $I_{c,d}$. Also, I think this ideal $I_{c,d}$ can answer the second part of the question, but it seems like there ought to exist a better example.  Is this right? Or at least a start in the right direction?  Any help appreciated!

Well, the problem I'm trying to solve is this:      Let $A$ be the ring of all continuous functions from $\mathbb{R} \to \mathbb{R}$. Show that $M = \{f \in A: f(0)=0\}$ is a maximal ideal of $A$.   I tried to show that if $J$ is an ideal of A that properly contains M, so $J = A$: we know that there is a function $g \in J$ with $g(0) \neq 0$. So, we have that $$J \supseteq \langle g, M\rangle=\{ag+f;a \in A, f\in M\}$$   I tried to show that 1 $\in$ $\langle g,M\rangle$. However I'd have to find some function $h(x)\in A$ such that $h(x)(ag+f) = 1$, but this function $h$ has to be different from 0 for all x $\in \mathbb{R}$, so I don't know how to find this function.  My second idea to solve this problem was prove that the quocient $A/M$ is a field. We have that $$A/M = \{h(x) + M; h(x) \in A\},$$ but again I have the problem to show that all elements of $A/M$ are units.  If someone could help, I would be really grateful (:


In The Lord of The Rings: The Fellowship of The Ring, the Fellowship passes through the Mines of Moria, which is an evil infested wasteland. It is unknown to Gimli how this happened as he still thought it would be maintained by Dwarves. I've also heard somewhere else in LOTR of someone being referred to as a refuge of Moria. So my question is; how did Moria go from a Dwarven mine to an evil-filled hole? If it mentions this in the book I may have missed it.

Between Gandalf's fear of Moria, and the amount of time that has obviously passed (due to the condition of the remains of the dwarves in Moria), why is Gimli so unaware of the fall of his kin?  At least in the movie, Saruman's line;      "Moria... You fear to go into those mines. The dwarves delved too   greedily and too deep. You know what they awoke in the darkness of   Khazad-dum... shadow and flame."   Would seem to indicate Gandalf not only knows of Balin's defeat, but even that the defeat was not purely because of orcs or goblins.  (The dwarves book of records references the drumming that is a precursor to the appearance of the Balrog - indicating the downfall of the dwarves in general was not due entirely to warring with the orcs).    I have a hard time believing Gandalf would have been so reluctant to go into Moria if he believed the Balin and his group of dwarves had been successful and wasn't more aware of its current state.  I figure even if he wasn't sure, he was pretty convinced they had not survived.  So why does Gimli seem so clueless (yes, I understand wizards are wise and a little smarter, but Gimli wasn't a neanderthal either.      I do not remember this part of the book really at all.  If things are entirely different in the book it wouldn't surprise me one bit.  If the answer is that Jackson took a liberty here for the sake of the movie's plot, I'd love to know the comparable aspects of the original version in the books as are applicable.


My opponent in a multiplayer game had exiled 2 cards I controlled during a recent game with an  like ability.  On my next turn I hit him for lethal.  What happens when he loses the game? Do the 2 cards remain exiled or do they re-enter play under my control?

In Magic: The Gathering, the rules for a player losing in a multiplayer game are quite complex, so I'd like to try to understand them by example. I would be happy to ask each of these situations as a separate question if that is preferred, but they all seem related, and I would love to have one place to look up all of these answers.  Let's say I'm playing with two friends, Bob and Chloe, in a simple free for all. Unfortunately, I lose. When I lose, suppose the following:   I controlled an  which has exiled Bob's , does he get his bear back? I have a  on the stack targeting Chloe, does Chloe take the 2 damage still? Earlier in the turn I cast  to prevent damage to one of Bob's . If it later takes 3 damage, will that damage be prevented? Something I controlled gave Bob a 1/1 soldier token. What happens to the token? Something Chloe controlled gave me a 1/1 soldier token. What happens to the token? I had a  enchanting one of Bob's army of . What happens to the bear? I had also played  on Bob's final . What happens to the last bear? Chloe had  my . What happens to the Clone? Are there any other situations specifically addressed by the rules?


I am getting the following error while trying to install skype  Failed to download repository information check your internet connection  E:The repository 'http://archive.ubuntu.com/ubuntu yakkety Release' does not have a Release file. W:Updating from such a repository can't be done securely, and is therefore disabled by default. W:See apt-secure(8) manpage for repository creation and user configuration details. E:The repository 'http://security.ubuntu.com/ubuntu yakkety-security Release' does no longer have a Release file. W:Updating from such a repository can't be done securely, and is therefore disabled by default. W:See apt-secure(8) manpage for repository creation and user configuration details. E:The repository 'http://in.archive.ubuntu.com/ubuntu yakkety Release' does no longer have a Release file. W:Updating from such a repository can't be done securely, and is therefore disabled by default. W:See apt-secure(8) manpage for repository creation and user configuration details. E:The repository 'http://in.archive.ubuntu.com/ubuntu yakkety-backports Release' does no longer have a Release file. W:Updating from such a repository can't be done securely, and is therefore disabled by default. W:See apt-secure(8) manpage for repository creation and user configuration details. E:The repository 'http://in.archive.ubuntu.com/ubuntu yakkety-updates Release' does no longer have a Release file.

I want to install Skype, but I can't locate it in Software Center or by using Synaptic Package Manager. Can anyone help me?


I have performed a mixed model logistic regression using glmer and used afex::mixed to obtain the correct pvalues.  mixed(model_9, data = ReversalTaskData, method = "PB", test_intercept = T,        family = "binomial")   but I receive this message  Formula (the first argument) converted to formula. Numerical variables NOT centered on 0: Stimulation, Block If in interactions, interpretation of lower order (e.g., main) effects difficult.  I was wondering if lmertest can be used as well obtain p-values in case of logistic (thus, non-linear) mixed model regression. do you have any other suggestion, otherwise?

I use lme4 in R to fit the mixed model  lmer(value~status+(1|experiment)))   where value is continuous, status and experiment are factors, and I get  Linear mixed model fit by REML  Formula: value ~ status + (1 | experiment)    AIC   BIC logLik deviance REMLdev  29.1 46.98 -9.548    5.911    19.1 Random effects:  Groups     Name        Variance Std.Dev.  experiment (Intercept) 0.065526 0.25598   Residual               0.053029 0.23028  Number of obs: 264, groups: experiment, 10  Fixed effects:             Estimate Std. Error t value (Intercept)  2.78004    0.08448   32.91 statusD      0.20493    0.03389    6.05 statusR      0.88690    0.03583   24.76  Correlation of Fixed Effects:         (Intr) statsD statusD -0.204        statusR -0.193  0.476   How can I know that the effect of status is significant? R reports only $t$-values and not $p$-values.


If I cycle the same route every day, what would be the benefit of having a power meter over a speedometer?  Can't I just measure my speed and compare it against my last run and see if I've done better?

I am currently using a IpBike computer app (on Android) with DuoTrap Speed and Cadence sensors on my bike. I was reading about power meters and how they would help in training by assessing the power output. However, I have some questions as mentioned below.  Can somebody explain the differences between power meter and bike computer? Are there any overlapping features between the two? or are they totally different from each other?  Also - having a power meter but not a bike computer, will it serve any purpose?  Thanks.


froze my computer importing a CT set, and not finding any way to fix it, I held the power button 'til it shut off.  Booting up, after selecting 'Ubuntu' from the boot menu, I am met with a black screen saying:     lvmetad is not active yet, using direct activation during sysinit   /dev/mapper/ubuntu--vg-root contains a file system with errors, check   forced. Inodes that were part of a corrupted orphan linked list found.      /dev/mapper/ubuntu--vg-root: UNEXPECTED INCONSISTENCY; RUN fsck   MANUALLY. (i.e., without -a or -p options) fsck exited with status   code 4 The root filesystem on /dev/mapper/ubuntu--vg-root requires a   manual fsck      BusyBox v1.22.1 (Ubuntu 1:1.22.0-15ubuntu1) built-in shell (ash) Enter   'help' for a list of built-in commands.      (initramfs)   Typing 'help', 'fsck' is not one of the listed built-in commands. Typing 'exit' repeats the message and brings me back to the (initramfs) prompt. Typing 'fsck' returns fsck from util-linux 2.27.1 and returns me to the (initramfs) prompt.  How do I fix the installation?

Ubuntu doesn't boot up and it goes into initramfs. I am writing from a live CD trial session. what should I do?  I understand that the boot flow is broken and that when the files from root are going to be loaded into the ram, it does not find the files in the root directory. Please correct me if I'm wrong.  The following is the output from ashell as I input the "exit" command:  (initramfs) exit /dev/mapper/ubuntu--vg-root contains a file system with errors, check forced. Inodes that were part of a corrupted orphan linked list found.  /dev/mapper/ubuntu-vg-root: UNEXPECTED INCONSISTENCY; Run fsck MANUALLY.     (i.e., without -a or -p options)  fsck exited with status code 4. The root file system on /dev/mapper/ubuntu--vg-root requires manual fsck


In Rudin's Real and Complex Analysis, the Lebesgue integral is defined as:  L et $(X,m,\mu)$ be a measure space, where $X$ is a set, $m$ is a $\sigma$ algebra on $X$ and $\mu$ is a measure. Then, if $f:X \to [0,\infty]$ and $E \in m$, we define $$\int_E f d\mu  = \sup \int_E s d\mu \tag{1}$$ where the supremum is taken over all simple functions $s, 0 \leq s \leq f$   I do not have much background in measure theory, and I am wondering why we assume $f$ to be measurable to define its integral.  EVEN IF $f$ is not a measuarable function, the above definition (1) would still be well-defined.   Why do we define integral only for measurable $f$?

In what follows I'm only considering positive real valued functions.  Everywhere I look about the definition of the Lebesgue integral it is required to consider a measurable function. Why do we not define the integral for non-measurable functions? From what I see we require measurablility of the simple functions that approximate f, not f itself. The definition I'm considering is given a measure space $X$ with measure $\mu$ and a measurable function $f$ we define  $$ \int_E f \, \mathrm{d}\mu = \sup_{s \in S} \int_X s \,\mathrm{d}\mu $$ where $S = \{ s : X \to [0, \infty) \mid 0 \le s \le f, s \text{ is simple, measurable} \}$.  For example consider $\mathbb{R}$ with the sigma algebra $\varnothing, \mathbb{R}$ with measure $\mu$ given by $\mu(\varnothing) = 0, \mu(\mathbb{R}) = 1$ and consider $f = \chi_{[0,1]}$ then why can't we say that $$ \int_{\mathbb{R}} f \,\mathrm{d} \mu = 0 $$ (since the only measurable simple function such that $0\le s \le f$ is $s = 0$) which would follow the definition above? Is this not well defined? In general I'm struggling to see why measurable functions (other than measurable simple functions) are used.


I read the guide for bounties and it is stated that after 24 hours of deadline to the bounty, if the answer is not selected, it will be awarded automatically. But there was no explanation of how it will be done.   I read other expired bounty questions but didn't find how it is taken care of?  So, how is it going to be given? Manual Check for best answer as per moderators or automatic assignment over most upvote, most recent?

It's possible to offer and award bounties of reputation on questions.   What is a bounty? How can I find questions that have a bounty attached? How do I start a bounty? When can I start a bounty? Why is the system requiring me to choose a bounty amount that's higher than the minimum? Can I use Markdown formatting in the bounty remarks? Can I edit the remark? How long is the bounty period? How do I award a bounty? Can I award a bounty to my own answer? Can I award a bounty to an old answer? If I offer a bounty on someone else's question, can I award the bounty to their answer? After awarding the bounty, can I remove it or move it to another answer at a later time? What happens if there's no answer after the bounty period? What happens if I feel my question is still unanswered? What is automatic awarding? Are bounty awards exempt from the 200 points/day reputation limit? How does Community Wiki mode affect bounties? How does user deletion or post dissociation affect bounties? Can I award a bounty to an answer from a deleted user or one where the author was dissociated? Can I offer a second bounty after the first one has expired? Can I raise my bounty? What happens if a bounty question is closed or deleted? Why can't I vote to close or migrate a bounty question? What happens if I delete my account while I have an active bounty? Do I keep an awarded bounty when I delete my answer? What happens if a question where I awarded a bounty later gets deleted or migrated? Can I cancel my bounty? Can I affect / divide / share part of my bounty to two (or more) users? How many outstanding bounties can a single user have?      See also:  in the Help Center


\documentclass {article} \usepackage {geometry} \usepackage {amsmath} \begin {document} With align* command :-\\ \\ \\ \begin {align*} a = b + c \\ abcd = f + g + h \end {align*}\\ \\ \\ \\ Without align* command :-\\ \\ \\ a = b +c \\abcd = f + g + h \\ \\ \\ With align* command and ''and'' symbol used:-\\ \\ \\ \begin {align*} a & = b + c \\ abcd & = f + g + h \end {align*}\\ \\ \\ \\ Without align* command and `'and'' symbol used :-\\ \\ \\ a &= b +c \\abcd &= f + g + h \\ \\ \\ \end {document}

Consider the following m(non-)we:  \documentclass{standalone} \begin{document} Foo & Bar \end{document}   The build will fail with  ! Misplaced alignment tab character &.   while it will generate a perfectly fine PDF when removing the & character from the code.  Even plain TeX behaves like that and  Foo & Bar \bye   yields the same error.  I have only ever seen & used in tabular and array environments, never outside of it. Why is that?  Couldn't one define e.g. \tabular and \endtabular so that & is only special inside the environment, and just a normal character outside of these environments?  Why does & outside of tabular and array environments have to break the document?  To rephrase the question: WTF is an alignment tab character and where do we usually put it?


To expand $f(z)=\sin(\frac{1}{z})$ about $z=0$? can someone do a step by step explained method please?

I am attempting to find the Laurent expansion at $z=0$  for $$f(z) = \sin {\frac{1}{z}}$$ where $z$ is a complex number. I rewrote the function as $$f(z)=\frac{ e^{iz^{-1}} - e^{-iz^{-1}}}{2i}$$ $$=\frac{1}{2i} \sum_{n=0}^{\infty}[i^n-(-i)^n]\frac{z^{-n}}{n!} $$  What do I do next?


My blender project has the mountain in cycles and the water in internal, how do i render both in one scene. But when i use render, i have to change the engine to see it.

I was watching a tutorial how to design an island in Blender, which worked really great, but i didn't want to use the .png Trees the guy used there. So i watched another tutorial and created another kind of tree - without knowing that the object isn't just modeled in Cycles Render, it is also rendered in there.  My problem is either the (lets say "simple" textured) island (rendered in Blender render) or the tree is shown. Is there any way i can "convert" that cycles object (with its shaders) to Blender Render or the other way around? Or just render with two renders in one project? I haven't found something about that til now. If there is no universal solution for that, i could also put a link to my project in here.


In Javascript, I'd like to have an object with three properties, "zone1", "zone2", "zone3", each of which store an array of place names.  I would like to search for a match by iterating through the arrays to find a place name. The following questions almost gets me there, but don't work for me because I am not using jQuery, and I want the value, not the key:       My code looks like this:  var zoneArray = {}; zoneArray["zone1"] = ["placeA", "placeB"]; zoneArray["zone2"] = ["placeC", "placeD"];  function getZone(place, zoneArray) {     var zone;     for (var key in zoneArray) {         for(i = 0; i<key.length; i++) {             if(key[i] == place) {                 zone = key;                 return zone;             }         }     }  } getZone("placeC", climateZoneArray);   Apparently however, "key[i]" is referring to letters of the zone names, like, "z" "o" "n" "e"  Could anybody please help me understand or best handle this situation in Javascript?

How do I enumerate the properties of a JavaScript object?  I actually want to list all the defined variables and their values, but I've learned that defining a variable actually creates a property of the window object.


I am trying to merge the following objects into one but having no luck so far - the structure is as follows in my console.log :      2018-05-11 : {posts: 2} // var posts     2018-05-11 : {notes: 1} // var notes   Once merged I want it to look like the following  2018-05-11 : {posts: 2, notes: 1}   I have tried object.assign() but it is just removing the initial posts data - what is the best approach for this?

I need to be able to merge two (very simple) JavaScript objects at runtime.  For example I'd like to:  var obj1 = { food: 'pizza', car: 'ford' } var obj2 = { animal: 'dog' }  obj1.merge(obj2);  //obj1 now has three properties: food, car, and animal   Does anyone have a script for this or know of a built in way to do this?  I do not need recursion, and I do not need to merge functions, just methods on flat objects.


print("Hello Welcome To The Essay Generating Code") print("") print("First things first, you need to give your essay characters") print("") print("") print("How many main characters would you like your story to have?") number_of_characters = input("Number Of Characters:") if number_of_characters <= "10":     print("That's way too many characters!")  else:     # rest of code   I would like to redirect the user with the else function back to input the number of characters, how do I do that?

Is there a goto or any equivalent in Python to be able to jump to a specific line of code?


As shown in the picture, there is no such option   it will show in the right corner, but it's not clickable.

I have inadvertently created an illustration with the align new objects to pixel grid turned on (not sure why it was on, I did not know or ever turn it on) and want to now scale the image. When I turned it off, I scale and it is still affecting the illustration.  So I copy and pasted it into a new document (Making sure that the option was turned of when I created the new document), and it is still affecting the illustration.  How can I scale this object without it being affected by this option?


I'm trying to solve a simple challenge that requires the code to return numbers (floats) rounded to 1 decimal point(s). The code is actually working but it seems that round() is not returning the correct result.  For example, the answer to one of the test cases I'm getting is 45357.45. When rounded to the first decimal, this should be 45357.5. But using round() is still returning 45357.4. I tested with the following numbers and I'm getting mixed results:  # Correct print(round(5.45, 1)) 5.5  # Incorrect print(round(5674.45, 1)) 5674.4   Why would this happen and is there a way to fix it?

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


when I execute   ffmpeg -i >video file> -r 24 -t 100 %d.jpeg   I see output lines like  frame= 47 ... time=6.70   which I guess is the time stamp of frame 47. But this data only shows up for some frames, can I get it to come for all frames?

ffmpeg -i myvid.mp4  -r  25  -t  100  image-%d.jpeg    Is the command I'm using to extract frames and it's working just like I expected. However I'd also like to look at the timestamps of the frames. At whatever precision. 100 miliseconds is good enough for me. Can ffmpeg do this?  Providing additional details,  When I run the above command i get around 100 JPEGs, I guess there is a 1 to 1 (or many to 1) correspondence between these JPEGS and frames of the video. I would like to know the timestamp of the frame that was output as a JPEG image 'i'.   Additionally I tried ffprobe but I find it reports even the video duration inaccurately :(


I've created this link:  sudo ln -s /etc/phpmyadmin/apache.conf /etc/apache2/conf-enabled/phpmyadmin.conf   I've tried to remove it in these ways:  sudo unlink /etc/phpmyadmin/apache.conf /etc/apache2/conf-enabled/phpmyadmin.conf sudo rm ln /etc/phpmyadmin/apache.conf /etc/apache2/conf-enabled/phpmyadmin.conf sudo rm ln -s /etc/phpmyadmin/apache.conf /etc/apache2/conf-enabled/phpmyadmin.conf   These three ways didn't work for me. What have I missed?

I was trying to create this symbolic link:  sudo ln -s /usr/share/phpmyadmin /var/www/phpmyadmin   but I accidentally typed:  sudo ln -s /usr/share/php,yad,in /var/www/phpmyadmin   So now I want to correct it but it says symbolic link already exist.


The fact that John was a good student resulted in his/him having many offers for the job.   Which one should be used and why?

The rule says that we can use a possessive adjective or an object pronoun before a gerund. Is there a rule  that says when to use each or are they interchangeable? Some say that it's wrong to use an object pronoun before a gerund.


Why am II still getting this warning after coming back from a suspension? Should I get a fresh start? Is this probation temporary?   Wait! Some of your past questions have not been well-received, and you're in danger of being blocked from asking any more. For help formulating a clear, useful question, see: How do I ask a good question? Also, edit your previous questions to improve formatting and clarity."  How important is getting up votes for this question after a warning like this? Does a better received question at this point get you another chance to ask a question?

If you are reading this, you may have been affected by one of our post quality bans. If so, it is important that you  to understand what has happened and how to regain the permissions that you lost. While trying to ask a question, one could see:  We are no longer accepting questions from this account. See  to learn more.  Likewise, for answers:  We are no longer accepting answers from this account. See  to learn more.   Why am I getting this message? Are deleted posts taken into account too? Is a question/answer ban the same as a suspension? How do I avoid getting a question ban? How long do I have to wait before I can post again? What can I do to release the ban? How can I reactivate my account? Can I simply create a new account? I'll just ask somewhere else on the SE network, and they'll migrate my question to the correct site! Will a ban on one Stack Exchange site affect my standing on other sites in the network? Does this apply to meta sites too? My account is in good standing. Why am I still blocked?


How can I retrive a numbers from array or list so I can use them as part of computation such as following :  \def\MaxValueArray{9220,1024,0.95,162.22}  \foreach \valBS  [count=\k] in {4089,512,0.65,125.85}{     \path (3*\A:\k) node[right,font=\tiny] {\k*\valBS/MaxValueArray[\k]};    I was not able to do that is there anyway I can retrieve the value from array by using an index to fetch it.

I would like to create something like a=array[1,2,15,6,18] and then a[0]=1, a[1]=2. Is it possible to create an array in LaTeX (with pgf or another package)?


I'm writing my final thesis and I need image illustration that one of my web input fields is sql injection safe! I have a php backend and a my sql database. I have used prepared statements for my queries so they should be safe right? However I need some screen dumbs of me trying to "hack" my input field to prove that it works. I'm not a hacker so I don't know any working examples. I know that I have to break the sql syntax somehow and then write some sql query that eventually would be run. I would like some really simple example, eventually truncate table or something like that, how can I illustrate this?    php Code that should be injection safe right? (please confirm ;)  if($action == 'layout'){ $pos = 1; foreach($_POST as $key => $value) {     if (strstr($key, 'se')){         $values = [];         foreach($value as $se) {             $values[] = $se;         }          $stmt = $mysqli_link->prepare("REPLACE INTO tblSvgElement(PlaceID, SVG, SVGPosition, Path1Color, Path2Color, Path3Color) VALUES (?,?,?,?,?,?)");         $stmt->bind_param("iissss", $zite_id, $values[0], $pos, $values[1], $values[2], $values[3]);         $stmt->execute();         $pos +=1;     } } $stmt->close(); $mysqli_link->close();   }

Just looking at:   (Source: )  What does this SQL do:  Robert'); DROP TABLE STUDENTS; --   I know both ' and -- are for comments, but doesn't the word DROP get commented as well since it is part of the same line?


Given $n$ prime numbers, $p_1, p_2, p_3,\ldots,p_n$, then $p_1p_2p_3\cdots p_n+1$ is not divisible by any of the primes $p_i, i=1,2,3,\ldots,n.$ I dont understand why. Can somebody give me a hint or an Explanation ? Thanks.

In Euclid's proof, if $p_1, p_2, \dots, p_n$ are the only primes then $p_1 \times p_2 \times \dots \times p_n + 1$ is not divisible by any of $p_1, p_2, \dots, p_n$ (because of some algebraic facts), which makes another prime and is a contradiction.   The proof makes sense logically, and I tried some numerical examples to "feel" the proof better but...  $2 \times 3 \times 5\times 7\times 11\times 13+1$ is not a prime! $2 \times 3 \times 5\times 7\times 11\times 13 \times 17+1$ is also not prime! Why is the general case proof is not working for these examples?


Update:  Please check the  linked by @Phill, verified on 10.15.4    I used csrutil disable to turn off System Integrity Protection and deleted some unused pre-installed apps before macOS 10.14. Recently, I upgraded to macOS 10.15 Beta (19A487l) and found this way didn't work anymore. My admin account only has Read-only access for pre-installed applications.  The /Applications in Terminal is actually /System/Volumes/USER-Data/Applications.  ➜  ~ ls /Applications        Alfred 4.app           Safari.app             Utilities Google Chrome.app      ShadowsocksX-NG.app    Visual Studio Code.app   I don't have write access to /System/Applications.  ➜  ~ sudo rm -rf /System/Applications/Stickies.app ... rm: /System/Applications/Stickies.app: Read-only file system   I also cannot change the privilege from Finder -> /System/Applications/Stickies.app -> Get Info -> Sharing & Permissions, it says:     The operation can’t be completed because you don’t have the necessary permission.   I've read  and chflags didn't work either because of Read-only.  How can I access to the "real" system account or is there the other way to delete or hide those applications?  Thank you.

> sudo rmdir /sw rmdir: /sw: Read-only file system  > mount | grep read /dev/disk1s5 on / (apfs, local, read-only, journaled)  > sudo mount -o rw / > mount /dev/disk1s5 on / (apfs, local, journaled) > sudo rmdir /sw rmdir: /sw: Operation not permitted     root />$ mkdir a root />$ rmdir a root />$ rmdir sw rmdir: sw: Operation not permitted root />$ rmdir opt rmdir: opt: Operation not permitted root />$ rmdir mnt rmdir: mnt: Operation not permitted root />$ rmdir home rmdir: home: Operation not permitted   What exactly is preventing me from removing these directories even with SIP disabled?


What just happened? I have a flash drive of mine with a lot of school files that I just planned on doing a format. So before I went to Disk Utility then erasing it to the format I wanted, First I backed-up all its files by creating a new folder on my desktop then just copy pasted all my files from the flash drive to this new folder I just created. Afterwards, I went on erasing my flash drive therefore losing all it's files but It's okay cause I did a backup anyways.   Now when I was just about to put the the files from the new folder to the newly formatted flash drive, I was about to select all by doing shortcut command "command + a" I accidentally pressed "command + z" instead doing an undo and all the files were lost! After that, finder doesn't even allow me to do a redo!   Please help those are a lot of important files now they're all gone in just 1 second and they're not even in the trash. I did a spotlight search of some files I can remember but I still can't find one!

I am a longtime Windows user, recently switched to Mac. I replaced folder with another folder (they had the same name) thinking that OS X will merge the contents of both folders. But OS X deleted the original folder and replaced it with the new one. Windows merges both the folders (I do this often in Windows). I have now lost hundreds of files. I haven't enabled Time Machine. I've tried using Finder's Undo, but that doesn't work.  Currently, I am trying to recover my data using . It shows estimated time as 7 hours, 31 minutes. Does anyone know any free data recovery software that's faster and more powerful?


Many sites use "Overflow" in their names:      Are any of these Stack Exchange sites? If so, what should a Stack Exchange site have that distinguishes it from other sites? (I'm not asking for legal advice, just info about if they're affiliated or not.)

I am considering registering a domain name in nameoverflow.com format.  Would doing so violate the trademark of /Stack Overflow Internet Services?  I ask because "overflow" can be a generic word.  I will not use Stack Overflow-like design on my domain, nor will my site be a Stack Exchange site.


I have a question. I want to check whether the following limit exists:  $$\lim_{(x,y) \rightarrow (0,0)} \frac{xy}{|x|+|y|}.$$   I have already searched on the internet and they say many different things. In my own book there stood that it doesn't exist. Is that true? And how do you show that it doesn't or does exist by this limit?  Thank you

I have this function:  $$ f(x,y) = \frac {xy}{|x|+|y|} $$  And I want to evaluate it's limit when $$ (x,y) \to (0,0)$$ My guess is that it tends to zero. So, by definition, if:  $$ \forall \varepsilon \gt 0, \exists \delta \gt 0 \diagup \\ 0\lt||(x,y)||\lt \delta , \left|\frac{xy}{|x|+|y|}\right| \lt \varepsilon $$ Then $$ \lim_{(x,y)\to(0,0)}\frac {xy}{|x|+|y|} = 0 $$ So:  $$ \left|\frac{xy}{|x|+|y|}\right| = \frac{|xy|}{|x|+|y|} = \frac{|x||y|}{|x|+|y|} \le 1 |y| \lt \delta $$  So for any $$\delta \lt \varepsilon$$ the inequality is true. Hence, the limit exists and is equal to zero.  . Am I wrong or is Wolfram|Alpha wrong?


for (var i = 0; i < 10; i += .1) { }  console.log(i) === 10.09999999999998    BUT ...  for (var i = 0; i < 10; i += 1/8) { }  console.log(i) === 10   Why is the result an integer when increment by 1/8?

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


I know there are potentially ways to do this by putting your dropbox folders within your Google Drive folder, but it makes me a bit nervous. I have plenty of room on my hard drive, so figured maybe the best solution would be to just have a secondary directory tree for Google Drive that would "mirror" most of the folders from my Dropbox folder tree.  However, I don't want to have to manually manage every time I make changes.  I'm wondering if there is an application that would either immediately or on a schedule (say every night at 3am), make the changes in the Google Drive folder that had just been made in the Dropbox one?  I'm sure there are probably many out there that do this, but I guess I'm looking for the most reliable, well-known ones, preferably free, or at least under $20 if possible.

I am interested in using Dropbox and Google Drive to sync the same folder at the same time...  Is there any special consideration to be taken into account?  Any help is apreciated.


I have a database which takes up 500gb, I have noticed that my ple is low even though I have 100gb of RAM. I have searched in google to find reasons of that and I found some interesting queries. I have a query which runs on very big table even though it uses clustered index it causes ple to drop. I checked  what is in buffer pool before and after query and moment after query is done and it looks like DB has to free some space for index used in my query and after query old indexes are loaded to the buffer pool. My question is how much RAM memory should DB have, how could I calculate it, should it be amount which will let me keep all used indexes in memory at once? Or maybe I should reduce data kept in tables so indexes will be smaller?

I'm trying to come up with a sane way to understand if the max server memory (mb) setting is appropriate (either should be lower, or higher, or stay the way it is).  I am aware that max server memory (mb) should always be low enough to leave room for the operating system itself, etc.    The environment I'm looking at has several hundred servers; I need a reliable formula I can use to determine if the present size of the buffer pool is appropriate since RAM is costed per GB allocated to each server.  The entire environment is virtualized, and "physical" RAM allocated to a VM can easily be changed up or down.  I have a particular SQL Server Instance I'm looking at now with a PLE of 1,100,052 seconds, which equates to 12.7 days (the amount of time the server has been up).  The server has a max server memory setting of 2560MB (2.5GB), of which only 1380MB (1.3GB) is actually committed.    I've read several items including one by Jonathan Keheyias () and another by Paul Randal (), and several others.  Jonathan advocates monitoring for a PLE below 300 per 4GB of buffer pool as being too low.  For the SQL Server Instance above, 300 * (2.5 / 4) = 187 results in a really really low target PLE below 300.  This instance has 290GB of SQL Server data (not including log files), and is only used for integration testing.  Assuming the last 12 days is representative of typical usage for this server, I'd say the max server memory (mb) setting could be lowered.  At the other end of the scale, I have another integration-test server with a PLE of 294, that has a max server memory (mb) setting of only 1GB.  This server has only 224MB of SQL Server data not including logs, and is running some BizFlow databases.  This server might benefit from a higher max server memory (mb) setting.  I'm thinking a good starting place for targets that might be assigned too much memory could include looking at:  SELECT      RamMB = physical_memory_in_bytes / 1048576     , BufferPoolCommittedMB = bpool_committed * 8192E0 / 1048576     , BufferPoolCommitTargetMB = bpool_commit_target * 8192E0 / 1048576     , PercentOfDesiredSizeMB = CONVERT(INT,(CONVERT(DECIMAL(18,2),bpool_committed)                              / bpool_commit_target) * 100) FROM sys.dm_os_sys_info;   If BufferPoolCommitTargetMB / BufferPoolCommittedMB is greater than 1, the server is not using the entire buffer pool.  If the machine in question also has a PLE of greater than "x" then it might be a good candidate for a decrease in max server memory (mb).  Since the Buffer Manager:Lazy writes/sec performance counter tracks the number of times SQLOS has written pages out to disk between checkpoints due to memory pressure, this might be another good thing to look at.  DECLARE @WaitTime DATETIME; SET @WaitTime = '00:00:15'; DECLARE @NumSeconds INT; SET @NumSeconds = DATEDIFF(SECOND, 0, @WaitTime); DECLARE @LazyWrites1 BIGINT; DECLARE @LazyWrites2 BIGINT;  SELECT @LazyWrites1 = cntr_value  FROM sys.dm_os_performance_counters dopc WHERE (         dopc.counter_name LIKE 'Lazy writes/sec%' COLLATE SQL_Latin1_General_CP1_CI_AS     )     AND dopc.object_name = 'MSSQL$' + CONVERT(VARCHAR(255),                SERVERPROPERTY('InstanceName')) + ':Buffer Manager';  WAITFOR DELAY @WaitTime;  SELECT @LazyWrites2 = cntr_value  FROM sys.dm_os_performance_counters dopc WHERE (         dopc.counter_name LIKE 'Lazy writes/sec%' COLLATE SQL_Latin1_General_CP1_CI_AS     )     AND dopc.object_name = 'MSSQL$' + CONVERT(VARCHAR(255),                SERVERPROPERTY('InstanceName')) + ':Buffer Manager';  SELECT LazyWritesPerSecond = (@LazyWrites2 - @LazyWrites1) / @NumSeconds;   The above code assumes the server is under load during the 15 seconds it takes to run, otherwise it will report 0; which might be a misleading false-negative.  Should I also look at PAGELATCHIO_* wait stats or some other wait type as an indicator of memory pressure, or lack thereof?   My question is, how can I reliably determine a "good" target value for PLE and max server memory (mb)?


What are the benefits of buying iCloud storage ? What's the point? What is it for? I bought some and I unfortunately thought it would give me more space for apps or photos but it still says I don't have storage so I guess not I just like to know what's the point of it what is it used for and if there are any other ways to free up space without deleting stuff.

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.


If my role (let's say the Scientist) has 4 cards of the same color but was not able to get to a research station.  And, let's say a different player (the Operations guy) lands on the same city as the Scientist and in his last action he builds a research facility in that city. The Scientist is now in the city with the research facility, but just as it is now the Scientist's turn, there is only 1 card remaining in the player deck.  Did the team run out of time?  Technically, as the player's turn begins with actions, the Scientist can cure the last disease before having to draw the 2 cards which would result in the game ending--except that the cure had been placed on the board ending the game in a win.  So, can a turn begin when there is only 1 card in the player deck, or must there be 2?

Does a player need to complete a full turn (i.e. 4 actions, pickup, infect) if during the action portion the final disease was cured? I only ask because there was only 1 player card left in the deck and I wouldn't have been able to complete a full turn, which in the rules, signifies that players have lost. However, I knew that I could cure the final disease in one action.


So I've been trying to get big factorials like 50 using BigInteger. But when i run this program in cmd, i get unexpected error at line 16: fact=fact.multiply(new BigInteger(getFactorial(n-1))). I am not even able to see the thrown exception as it gets scrolled out. Please help me find the error.  import java.math.BigInteger; class FactorialUsingRecursion {  public static void main(String args[]) {     int num=50;     String fact=getFactorial(num);     System.out.println(num+"! = "+fact); }  static String getFactorial(int n) {     BigInteger fact=new BigInteger(n+"");      if(fact.toString()=="1") {         return "1";     }     fact=fact.multiply(new BigInteger(getFactorial(n-1)));//error line     return fact.toString(); } }

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?


Let $p$ a prime number such that $p≡3$ (m0d $4$), and $p>3$, discuss the factorization of $(p)$ in $\mathcal{O}_K$, where $K=\mathbb{Q}(\sqrt[4]{3})$.  I know that the ring of integers in this case is $\mathbb{Z}[\sqrt[4]{3}]$,and  by Kummer's theorem, one can decide the decomposition based on factorization of $f(x)=x^4−3$ (mod $p$). There are five possible cases:  $f(x)$ factors into $4$ linear factors in $\mathbb{F}_{p}[x]$. $f(x)$ factors into $2$ linear factors and $1$ irreducible quadratic factors in $\mathbb{F}_{p}[x]$. $f(x)$ factors into $2 $ irreducible quadratic factors in $\mathbb{F}_{p}[x]$. $f(x)$ factors into $1 $ linear factor and $1$ irreducible cubic factor in $\mathbb{F}_{p}[x]$. $f(x)$ is irreducible in $\mathbb{F}_{p}[x]$.  I don't know how to go further than this!

So I am trying to show that $f(x) = x^4-3$ will factor over $\Bbb{F}_p$ when $p\equiv 3\mod 4$, with $p\neq 3$. Specifically, I am trying to show that $f$ will factor into irreducibles such that there is at least one factor of degree 2.  My Work So Far  So if I assume that it can be factored, we would have $$ x^4-3 = (x^2+ax+b)(x^2-ax+d) = x^4 + (b+d-a^2)x^2 + a(d-b)x + bd.$$ Because we want the linear term to be 0, we need either $a=0$ or $d-b = 0$. Now if $a=0$ we get that $b=-d$, so $-b^2 = -3$. That is, $3$ is a square. If $d-b = 0$, then we would have $b^2 = -3$, so $-3$ is a square. Because $-1$ is not a square when $p\equiv 3\mod{4}$, we know that one of $-3$ or $3$ must be a square, but not both, so $a=0$ or $d=b$, but not both.  If $a=0$, that is $3$ is a square, then we have $f(x) = (x^2 +b)(x^2-b)$. Then one of $b$ or $-b$ is a square, but not the other, so $f$ will factor into two linear terms and a quadratic. So this case works.  The trouble I am having is with the second case. If $d=b$, then we have  $$ f(x) = (x^2 + ax + b)(x^2 -ax +b)$$ with $2b = a^2$. This is where I get stuck. How do I know that such an $a$ can exist?  Edit: If there is a better approach to solving this, that would be great to know as well. I haven't been taught any of the relevant number theory to solve this, so I'm kind of out of my element here.


I have a binary file that stops running every few weeks, you can simply start it again and it runs for another few weeks. The software is not perfect but it would be perfect enough if it restarted automatically.  What is the best way to set something up to automatically check if the binary is running and start it if it is not?

I have some applications that need to run on my laptop all the time.   I use a bash script to start these applications. In my script I have a loop that looks similar to this:    while true; do     xterm done   This runs an application (xterm in this case) and if the application crashes, the loop starts it again.    This has a disadvantage that there is no "clean" exit from this loop. So even if the intention of the user is to close xterm, the loop starts it again.    Is there a way to start an application from bash script, watch whether it is running, to re-run it if script crashed or do nothing if the user closed it properly ?


I'm trying write a report in LaTeX but TeXstudio won't let me. All I have is this:  \documentclass[a4paper,11pt]{report} \usepackage[T1]{fontenc} \usepackage[utf8]{inputenc} \usepackage{lmodern} \usepackage{graphicx}  \title{----} \author{---\\By: ----}  \begin{document}  \maketitle \paragraph{1} \paragraph{2}  \subparagraph{Red}$\\$ \includegraphics{Red} \subparagraph{Blue}$\\$ \includegraphics{Blue}  \end{document}   But when I click F1 to compile, TeXstudio spits this message:  Error: Could not start the command: pdflatex.exe -synctex=1 -interaction=nonstopmode "Prelab1".tex   What is the problem? Why can't I compile?   P.S: Ever since I switched from Ubuntu back to windows, writing LaTeX documents has been a massive pain T.T. What is the best LaTeX editor that won't give me a problem every single second?

I just downloaded and installed Texmaker. I've never used any (La)TeX before.  When I click the Run button with an arrow next to "Quick build" I get an error saying "Could not start the command". Why? What do I need to do?


I have a table that I would like to be fully centered. I have tried using \centering but that hasn't worked.  My code is   \begin{table}     \begin{tabular}{|p{5cm}|p{1.4cm}|p{5cm}|p{1cm}|p{3.5cm}|}         \hline          More/Less(IV) of& Leads to & More/Less of (DV) & Due to & Reason\\          \hline          An increase in worldwide internet coverage & results in & an increase of video games with online functionality  & Due to & an increasing number of customers with internet \\          \hline     \end{tabular} \end{table}   It ends up looking like this

I have a table that I want to insert on a page, but at least one (perhaps both) of the following conditions are met:   The table is too wide to fit within the text block or page. That is, I'm exceeding some horizontal restriction. The table is too tall to fit within the text block or page. That is, I'm exceeding some vertical restriction.   What are my options to make this table fit? If it doesn't fit, regardless of my attempts, what other options exist?


I recently installed Ubuntu 20.04 on a dual boot with Windows 10 but from the start the grub boot loader is black and white. Now it's not much of a problem because the operating systems itself work alright but I think I would rather choose to stare at a purple screen at the start rather than a black and white one.  Thanks for any solutions 😁.

How to do this manually, not installing any tools?