as we speak my disk space is lowering, ubuntu 16.04. What should i do to stop that? and maybe delete these huge files that are created?   4,0K    /srv 13M /bin 16K /lost+found 432K    /tmp 4,6M    /libx32 1,1T    /var 4,0K    /ptions 4,0K    /mnt 1,2G    /lib 8,0K    /snap 518G    /home 15M /sbin 311M    /opt 4,0K    /lib64 3,9M    /lib32 8,0K    /media 21M /etc 13G /usr 1,4G    /root 4,0K    /cdrom 1,6T    /   Using ncdu   -- /var/log/cups -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------                          /..                                                                                704,0 GiB [##########]  error_log   321,2 GiB [####      ]  error_log.1     2,4 GiB [          ]  error_log.7.gz     1,6 GiB [          ]  error_log.4.gz     1,6 GiB [          ]  error_log.3.gz     1,5 GiB [          ]  error_log.5.gz     1,3 GiB [          ]  error_log.2.gz     1,2 GiB [          ]  error_log.6.gz   570,5 MiB [          ]  error_log.1.gz   410,9 MiB [          ]  error_log.1.gz-2019042212.backup     4,0 KiB [          ]  access_log.1     4,0 KiB [          ]  access_log.4.gz     4,0 KiB [          ]  access_log.2.gz     4,0 KiB [          ]  access_log.7.gz     4,0 KiB [          ]  access_log.5.gz     4,0 KiB [          ]  access_log.6.gz     4,0 KiB [          ]  access_log.3.gz     0,0   B [          ]  page_log     0,0   B [          ]  access_log   edit, using tail to error_log  E [08/Feb/2020:12:07:33 +0200] Directory \"/usr/lib/cups/notifier\" has insecure permissions (040777/uid=0/gid=0). W [08/Feb/2020:12:07:33 +0200] Notifier for subscription 1695 (dbus://) went away, retrying! E [08/Feb/2020:12:07:33 +0200] Directory \"/usr/lib/cups/notifier\" has insecure permissions (040777/uid=0/gid=0). W [08/Feb/2020:12:07:33 +0200] Notifier for subscription 1695 (dbus://) went away, retrying! E [08/Feb/2020:12:07:33 +0200] Directory \"/usr/lib/cups/notifier\" has insecure permissions (040777/uid=0/gid=0). W [08/Feb/2020:12:07:33 +0200] Notifier for subscription 1695 (dbus://) went away, retrying! E [08/Feb/2020:12:07:33 +0200] Directory \"/usr/lib/cups/notifier\" has insecure permissions (040777/uid=0/gid=0). W [08/Feb/2020:12:07:33 +0200] Notifier for subscription 1695 (dbus://) went away, retrying! E [08/Feb/2020:12:07:33 +0200] Directory \"/usr/lib/cups/notifier\" has insecure permissions (040777/uid=0/gid=0). W [08/Feb/2020:12:07:33 +0200] Notifier for subscription 1695 (dbus://) went away, retrying!   so i did, and it stopped the on-growing file:  sudo chmod 755  /usr/lib/cups/notifier sudo service cups restart   and then  sudo rm   all error_log files

( deals with a similar issue, but it talks about a rotated log file.)  Today I got a system message regarding very low /var space.   As usual I executed the commands in the line of sudo apt-get clean which improved the scenario only slightly. Then I deleted the rotated log files which again provided very little improvement.  Upon examination I find that some log files in the /var/log has grown up to be very huge ones. To be specific, ls -lSh /var/log gives,   total 28G -rw-r----- 1 syslog            adm      14G Aug 23 21:56 kern.log -rw-r----- 1 syslog            adm      14G Aug 23 21:56 syslog -rw-rw-r-- 1 root              utmp    390K Aug 23 21:47 wtmp -rw-r--r-- 1 root              root    287K Aug 23 21:42 dpkg.log -rw-rw-r-- 1 root              utmp    287K Aug 23 20:43 lastlog    As we can see, the first two are the offending ones. I am mildly surprised why such large files have not been rotated.  So, what should I do? Simply delete these files and then reboot? Or go for some more prudent steps?  I am using Ubuntu 14.04.  UPDATE 1  To begin with, the system is only several months old. I had to install the system from scratch couple of months back after a hard disk crash.  Now, as advised in ,  I first checked the offending log files using tail, no surprise there. Then, for deeper inspection, I executed this script from the .  for log in /var/log/{syslog,kern.log}; do    echo "${log} :"   sed -e 's/\[[^]]\+\]//' -e 's/.*[0-9]\{2\}:[0-9]\{2\}:[0-9]\{2\}//' ${log} \   | sort | uniq -c | sort -hr | head -10 done   The process took several hours.  The output was in the line of,   /var/log/syslog : 71209229  Rafid-Hamiz-Dell kernel:  sda3: rw=1, want=7638104968240336200, limit=1681522688 53929977  Rafid-Hamiz-Dell kernel:  attempt to access beyond end of device 17280298  Rafid-Hamiz-Dell kernel:  attempt to access beyond end of device    1639  Rafid-Hamiz-Dell kernel:  EXT4-fs warning (device sda3): ext4_end_bio:317: I/O error -5 writing to inode 6819258 (offset 0 size 4096 starting block 54763121030042024)        <snipped>  /var/log/kern.log.1 : 71210257  Rafid-Hamiz-Dell kernel:  attempt to access beyond end of device 71209212  Rafid-Hamiz-Dell kernel:  sda3: rw=1, want=7638104968240336200, limit=1681522688    1639  Rafid-Hamiz-Dell kernel:  EXT4-fs warning (device sda3): ext4_end_bio:317: I/O error -5 writing to inode 6819258 (offset 0 size 4096 starting block 954763121030042024)    (/dev/sda3 is  my home directory. As we can find,   lsblk /dev/sda NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT sda      8:0    0 931.5G  0 disk  ├─sda1   8:1    0 122.1G  0 part / ├─sda2   8:2    0   7.6G  0 part [SWAP] └─sda3   8:3    0 801.8G  0 part /home    Why a process will want to write beyond the limit is actually outside the scope of my comprehension. Perhaps I will want to ask a different question in this forum if this continues even after a system update.)  Then, from  (you may want to check  for a deeper understanding), I executed,   sudo su - > kern.log > syslog   Now, these files have zero sizes. The system is running fine before and after a reboot.   I will watch these files (along with others) in the next few days and report back should they behave out-of-line.  As a final note, both  the offending files (kern.log and syslog), are set to be rotated, as inspection of the files (grep helped) inside  /etc/logrotate.d/ shows.  UPDATE 2  The log files are actually rotated. Looks like the large sizes were attained on a single day.


I would like to ask if someone could help me how to reach the following equation. \begin{equation}     \sin(x) = x\left(1-\frac{x^{2}}{\pi^{2}}\right)\left(1-\frac{x^{2}}{4\pi^{2}}\right)\left(1-\frac{x^{2}}{9\pi^{2}}\right)\left(1-\frac{x^{2}}{16\pi^{2}}\right)\left(1-\frac{x^{2}}{25\pi^{2}}\right) \cdots \end{equation} Thank you in advance.

How to prove the following product? $$\frac{\sin(x)}{x}= \left(1+\frac{x}{\pi}\right) \left(1-\frac{x}{\pi}\right) \left(1+\frac{x}{2\pi}\right) \left(1-\frac{x}{2\pi}\right) \left(1+\frac{x}{3\pi}\right) \left(1-\frac{x}{3\pi}\right)\cdots$$


I am new to JAVA (Actually migrated to JAVA from C#) and creating a Application on NetBeans IDE 8.0.2 which contains following   Server Application (Java Application) <-- This contain my MainClass Network Layer (Java Class Library) Data Access Layer (Java Class Library)   I have successfully reference the .jar in each above layers by adding jar files Project Library in NetBeans as shown in below image    When i click on build in NetBeans it creates 'dist' folder under Server Application folder which contain Server_Application.jar and a 'lib' folder which contain Network_Layer.jar  I want to ask that did I reference it correctly ?  How to distribute these file ? Should i distribute all the .jar file (Data_Access_Layer.jar, Network_Layer.jar and Server_Application.jar) ? OR just distribute the 'dist' folder of Server Application.  I also want ask that if i convert Network_Layer.jar and Data_Access_Layer.jar to '.dll' and Server_Application.jar to '.exe' file will it work correctly ?  In C# same things creates .dll files and if i want to distribute it I simply make setup of these dll and exe files. How to do same thing in JAVA using NetBeans  (I don't want to wrap all .jar files into one)

Java is one of my programming languages of choice.  I always run into the problem though of distributing my application to end-users.  Giving a user a JAR is not always as user friendly as I would like and using Java WebStart requires that I maintain a web server.  What's the best way to distribute a Java application?  What if the Java application needs to install artifacts to the user's computer?  Are there any good Java installation/packaging systems out there?


We have this virtual machine that has Apache2 installed, we forgot to install a log rotate and we got 24gb of logs from Apache2, We removed those 24gb of log files but no changes occurred to the disk whatsoever, It was like I didn't removed the logs at all. Does any one understand what may have happened?  root@Web:~# cat /etc/*-release DISTRIB_ID=Ubuntu DISTRIB_RELEASE=10.04 DISTRIB_CODENAME=lucid DISTRIB_DESCRIPTION="Ubuntu 10.04.4 LTS"  root@Web:~# df -kh Filesystem            Size  Used Avail Use% Mounted on /dev/sda1              29G   27G  675M  98% / none                  744M  176K  744M   1% /dev none                  748M     0  748M   0% /dev/shm none                  748M  568K  748M   1% /var/run none                  748M     0  748M   0% /var/lock none                  748M     0  748M   0% /lib/init/rw none                   29G   27G  675M  98% /var/lib/ureadahead/debugfs  root@Web:~# du -kh /var/log/apache2 24G     /var/log/apache2  root@Web:~# rm /var/log/apache2/*  root@Web:~# du -kh /var/log/apache2 4.0K    /var/log/apache2  root@Web:~# df -kh Filesystem            Size  Used Avail Use% Mounted on /dev/sda1              29G   27G  673M  98% / none                  744M  176K  744M   1% /dev none                  748M     0  748M   0% /dev/shm none                  748M  568K  748M   1% /var/run none                  748M     0  748M   0% /var/lock none                  748M     0  748M   0% /lib/init/rw none                   29G   27G  673M  98% /var/lib/ureadahead/debugfs

Is there any locking on the content, imposed by the process if at all the process is using the file.  We host a JBoss app server on a RHEL 6.4 OS and due to the disk space constraints we have decided to remove the log files it generated till date.  However, if we delete the log file which is being used there could be few issues with the logging in jboss which eventually leads to the restart of Jboss App Server instance.  We we have decided to nullify the server.log which is being dynamically written by the JBoss app server process (checked with the fuser command) by using the below commands:  -- > server.log -- echo "" > server.log   None of the above commands worked. The size of the files still shows 500+ MB  How do I remove the contents of the file without deleting the file?


I just ran across  while on comment patrol. It seems normal in almost every regard... Except it isn't. For one, it's cut off - look at the source and you see that there's quite a bit more that isn't shown.  Another thing: the code block formatting is.. um... overflowing:    I don't know if this is an injection of some kind or what, but it certainly doesn't look good for security. What's wrong?

has a weird case of the mono, while .  Also, that question is missing some content at the end:


I'm manually converting a code in C to MATLAB.  The code contains assignments like the following,  y[10] = p[32]+(p[31]-p[32])*pow(p_c[0],p[34])/(pow(p_c[0],p[34])+pow(p[33],p[34]));  To use it in MATLAB, I am manually increasing the value of all indexes by 1, since the index in MATLAB starts from 1.  y[10+1] = p[32+1]+(p[31+1]-p[32+1])*pow(p_c[0+1],p[34+1])/(pow(p_c[0+1],p[34+1])+pow(p[33+1],p[34+1]));  Is there an easy way of doing this task? There are around 30 assignments like the above example and I am trying to avoid doing this manually.  Edit 1: Would it be possible to use regular expression? I can copy all the lines of code that contain assignment in a text file. Using regular expression, if I can locate [35](any number) replace with [35+1]. I'm not sure how to implement this in a code.  Edit 2:A sample of other assignments in the code.    y[0] = ct[0]-x[12];     y[1] = ct[1]-1*x[10]-x[23];      y[3] = p_c[6]+p_c[5];        y[4] = p_c[2];       y[5] = x_c[23]+x_c[10]+y_c[1];       y[6] = y_c[0]+x_c[12];       p[0] = 30;       p[1] = 12;       p[2] = 2;     p[3] = 0;     p[4] = 90;       p[5] = 45     dx[0] = FunctionForD(p[67], p[64], p[66], p[65], p[23], x_c[0], x_c[3], p[49])*p[23]-FunctionForA(y[28], y[29], p[23], y[16])*p[23]+FunctionForD(y[30], y[31], p[23], y[16])*p[23]-FunctionForA(p[134], p[133], p[132], p[130], p[131], p_c[2], p[23], x_c[21], x_c[0], p[49])*p[23];   //      dx[1] = FunctionFor2(p[169], p[167], p[168], p[166], p[23], x_c[1], x_c[17], p[49])

I don't really understand regular expressions.  Can you explain them to me in an easy-to-follow manner?  If there are any online tools or books, could you also link to them?


I am using a bibtex to manage my references in LaTeX by cite package. The normal behavior of this package is printing a bibliography of all cited references in the document, however, I want its complement. In other words, suppose that I have cited two references, but want the bibliography contain the third one, which I have not cited.  Question: How to print just all the entries of a bibliography file which are not cited?  For the application, I check manually to see which references are not cited in my document which is a boring workaround!  As a minimal working example for test, suppose that my bibliography file is biblio.bib with the following contents:      @ARTICLE{Grzymala-Busse_1997_Classification,       author = {Grzymala-Busse, Jerzy W.},       title = {Classification of Unseen Examples under Uncertainty},       journal = {Fundamenta Informaticae},       year = {1997},       volume = {30},       pages = {255--267},       number = {3},       month = jan     }     @INCOLLECTION{Skowron_2005_Approximation,       author = {Skowron, Andrzej and Åwiniarski, Roman and Synak, Piotr},       title = {Approximation Spaces and Information Granulation},       booktitle = {Transactions on Rough Sets {III}},       publisher = {Springer Berlin Heidelberg},       year = {2005},       editor = {Peters, James F. and Skowron, Andrzej},       number = {3400},       series = {Lecture Notes in Computer Science},       pages = {175--189},       month = jan     }     @INCOLLECTION{Yao_2012_Outline,       author = {Yao, Yiyu},       title = {An Outline of a Theory of Three-Way Decisions},       booktitle = {Rough Sets and Current Trends in Computing},       publisher = {Springer Berlin Heidelberg},       year = {2012},       editor = {Yao, JingTao and Yang, Yan and SÅowiÅski, Roman and Greco, Salvatore         and Li, Huaxiong and Mitra, Sushmita and Polkowski, Lech},       pages = {1--17},       month = jan     }   and a LaTeX file  \documentclass{article} \usepackage{cite}  \begin{document}     \cite{Grzymala-Busse_1997_Classification,Yao_2012_Outline}      \bibliographystyle{acm}     \bibliography{biblio.bib} \end{document}

This question led to a new package:      While reading papers, I put those that I'd like to refer to or mention in customized .bib files (one .bib file for each paper). (Thanks to  it's pretty easy and straight forward - they call it "collections").  My intention is that all entries in the .bib file should be mentioned in the text.  How to check which bibliography entries I have not referred to ?


Under windows, given a PID:  1) How to get the exact memory in bytes and 2) The exact CPU usage  consumed by that application right now?

I am trying to find out how much memory my application is consuming from within the program itself. The memory usage I am looking for is the number reported in the "Mem Usage" column on the Processes tab of Windows Task Manager.


Given sequence {$a_{n}$} and supposing its set of cluster points $S_{p}$ is non-empty and bounded above, prove that $\limsup\limits_{n\rightarrow\infty}a_{n} = \inf_{n \geq 1}\sup_{m \geq n}a_{m}$.  I started by setting $x=\inf_{n \geq 1}\sup_{m \geq n}a_{m}$ and $y=\limsup\limits_{n\rightarrow\infty}a_{n}$. This then means I would have to show that $y \leq x$ and $y \geq x$, but I'm not really sure how to do this.

Let $(x_n)$ be a sequence in $\mathbb R$. We call $y$ a cluster point of $(x_n)$ iff for every neighborhood $N$ of $y$ there are infinitely many $n$ such that $x_n \in N$. Let $C$ denote the set of cluster points of $(x_n)$.   By definition, $\limsup_{n \to \infty} x_n = \inf_n \sup_{k \geq n} x_k$.  Can you show me how to prove $\limsup_n x_n = \sup C$? Thanks.


I know that every adiabatic reversible process is an isentropic process.  Can a process be isentropic but still not reversible adiabatic?  Please provide me some examples.

recently wrote an  on  in collisionless , where at least one topic discussed confused me.  Besides discussing the issue of how a process can be microscopically  and macroscopically , he mentions something regarding a "entropy-preserving relaxation mechanism" that is irreversible.  Am I missing something?  I think the article is suggesting that something can preserve entropy but still be irreversible.  This begs the following questions:   Are  and irreversibility synonymous? Or are they distinct entities each with their own fundamental properties?


$(document).ready(function(){     $(".click").on('click', function(){         var target = $(this).parent().children(".expand");         $(target).slideToggle();     }); });   HTML content loaded by AJAX:
...div with expand ....

...div with expand ....
   Can any one correct my code? Thanks in advance!

I have a bit of code where I am looping through all the select boxes on a page and binding a .hover event to them to do a bit of twiddling with their width on mouse on/off.  This happens on page ready and works just fine.  The problem I have is that any select boxes I add via Ajax or DOM after the initial loop won't have the event bound.  I have found this plugin (), but before I add another 5k to my pages with a plugin, I want to see if anyone knows a way to do this, either with jQuery directly or by another option.


Greeting, friends,  A quick question: I am contemplating creating a "notebook" with some useful snippets of LaTeX code, examples, tips and tricks. All this stuff is accumulating in process of my work and I would like to have it in one documents for my own quick reference. I would like to have it arranged in LaTeX, obviously. Therefore, I would like to ask if anyone knows of a LaTeX package that can help to display LaTeX code and display it in aesthetically pleasing way, so it looks nice in resulting pdf document after compilation? Thank you!

I am writing some documentation for a LaTeX package, in which I am going to be including some example LaTeX code.  What is the best way to typeset that code?  I know I could just use verbatim, but it would be nice to get syntax highlighting.  I realize that this is a duplicate of , in which the consensus was to use the  package.  The problem with listings is that it seems to only have a driver for TeX, not LaTeX.  For example, when I typeset something like this:  \begin{lstlisting}[language=TeX,                    keywordstyle=\bfseries,                    identifierstyle=\itseries,                    stringstyle=\ttfamily] \begin{minipage}{\hsize}   This is a test! \end{minipage} \end{lstlisting}   it results in something like this:     \begin{minipage}{\hsize}     This is a test!   \end{center}   which is obviously messed up.  Is there a LaTeX-specific driver for listings?  If not, is there another package that does syntax highlighting for LaTeX code?


I'm looking for a word or two for a person who would support or defend either side of an issue for personal gain. In other words, a person who is not interested in truth for truth's sake but for personal gain or advantage.

Take this paragraph for example: I am a follower, not a leader. Hell, I'm not even that good of a follower either, just someone who will do your bidding for the right price. Even then, if it doesn't benefit me -- or put you in debt to me -- I won't do it.


This command lists all the files match the provided name:  find . -iname .DS_Store   But when I use -delete parameter with it, I can't see the list of deleted files. They just get deleted.  Preferably without making it complicated with | xarg .. or -exec rm {}, is there any magic flag to see the deleted files when using find . -iname .DS_Store -delete?  PS: I know I can run the command without delete flag before, but I'm looking for something like print0 (though prints uglily) to get the job done.

I use the following command in order to delete only the files that start with DBG and older then two day , but this syntax not print the files that deleted  find /tmp  -type f -mtime +2 -name "DBG*" -exec rm {} \;   How to add to this the find syntax , the print in order to print the deleted files?


I have a JSON data to post to http, this JSON data has a var named params:  {  "method": "...",  "params": [ ... ],  "session": "...",  "id": 1 }   I want to link every request and response to a class in my Models. How can I either use the name params for the attribute or make the attribute name change as I serialize my class to JSON format?  I am using ASP.NET MVC 4 and JSON.NET framework on visual studio 2013 Ultimate edition.

I discovered that you can start your variable name with a '@' character in C#.  In my C# project I was using a web service (I added a web reference to my project) that was written in Java. One of the interface objects defined in the WSDL had a member variable with the name "params". Obviously this is a reserved word in C# so you can't have a class with a member variable with the name "params". The proxy object that was generated contained a property that looked like this:  public ArrayList @params {     get { return this.paramsField; }     set { this.paramsField = value; } }   I searched through the VS 2008 c# documentation but couldn't find anything about it. Also searching Google didn't give me any useful answers. So what is the exact meaning or use of the '@' character in a variable/property name?


I am trying to convert a string to a double or float in C++, but the result is not exact. For example: double d1 = stod("2.16"); //d1 ends up being 2.1600000000000001  float f1 = stof("2.16"); //f1 ends up being 2.16000009  Is it possible to convert "2.16" to the actual value 2.16 ( 2.16000000 float or 2.1600000000000000 double) using C++ libraries? I need the exact values for some calculations so I don't need it to be printed as 2.16, I need the exact number.

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


I am reading "Commutative ring theory" by Matsumura, but find it a little hard. I wanted to find some reference books but found few books have the same details as CRT (for example, I can't find one with flatness in detail). So, please help me with some reference books.

I want to learn commutative algebra from scratch. I was wondering, as you are experts in mathematics, what you think is the best way to learn commutative algebra? Is there any video course available for commutative algebra? Will there be some online course for commutative algebra on some website like Coursera, etc?  I know noncommutative algebra up to the Artin-Wedderburn Theorem. Also, I know group theory up to the Sylow theorems and Galois Theory. I also know some basic topology.  I'm new to this site so I don't know what tags I should add for this question. Please feel free to edit my question.  Edit 1: I want to learn commutative algebra for learning Algebraic Geometry.


Suppose $E = \mathbb{Q}(\alpha_1,\alpha_2,...,\alpha_n)$ where $\alpha_i^2\in \mathbb{Q}$ for $i=1,2,...,n.$ Prove that $2^{1/3} \not\in E$.  I thought I could prove it by contradiction but I have made no progress. Can someone share some insights? Thanks a lot!

Let $F$ be the field $\Bbb Q(\alpha_1,...,\alpha_k)$ where  $\alpha_i^2\in\Bbb Q\ \forall i$  I want to show that $\sqrt[3]{2}\notin F$  I thought if $\sqrt[3]{2}\in F$ then $\sqrt[3]{2}\in\Bbb Q\cup(\alpha_1,...,\alpha_k)$ but this is not a disjoint union so I'm not sure what to do... taking the square of $\beta:=\sqrt[3]{2}$ gives $2^{2/3}=\sqrt[3]{4}\notin\Bbb Q$ but that doesn't really advance things  So I'm looking for a hint


I have a proof for it. I just want to make sure it's correct.   Assume, for the sake of contradiction, that $\sqrt{2}$ is rational.   Then, $\sqrt{2} = \frac{a}{b}$ (1) , where a and b are integers and gcd(a,b)=1.  Note that $\sqrt{2}$ is non-integer. Thus, b does not divide a  Squaring both sides of equation (1),  2 = $\frac{a^2}{b^2}$. This means that $b^2|a^2$   Let p be a prime where p|$a^2$. Then $p|a$  Now assume that p| $b^2$. Then p|b. However, this is a contradiction because $gcd(a,b)= 1$  Therefore, $gcd(a^2, b^2)=1$. However, this contradicts the earlier conclusion that $b^2|a^2$   Hence, $\sqrt{2}$ cannot be rational.   Therefore, $\sqrt{2}$ irrational.  Is there something wrong with this proof?

I'm trying to understand each part of this completed proof that my professor did, here is my interpretation in parentheses, please advise as necessary.  Proof: Assume that $2^{1/2}$ is rational, then $2^{1/2}$ = $p/q$ for some integer $p$ and $q$ with $q \neq 0$ and $\gcd(p,q) = 1$  $$(p/q)^2 = 2 = p^2 / q^2 $$ $$\text{ (What was the purpose of squaring √2 and p/q?)}$$  $$p^2 = 2q^2$$ $$ \text{ (Is this basically just canceling out the q^2 on left side, and multiplying the right side?)}$$  2 | p^2 => (2 divides p^2 since it is a factor)  2 | p => (thus 2 divides p)  p = 2k for some integer k => (definition of even)  (2k)^2 = 4k^2 = 2q^2 => (Why are we squaring 2k, and how does 4k^2 = 2q^2?)   q^2 = 2k^2 => (Canceled out 2 on one side, and dividing on other)  2 | q^2 => (2 divides q^2)  2 | q => (thus 2 divides q)  2 | gcd(p,q) => (2 divides gcd of p and q)  2 | 1 Which is a Contradiction (no clue how I got here)


When installing Ubuntu 18.04 LTS when the installation comes to the installation of "grub 2", it terminates and gives an error:  could not install the grub bootloader into target.   But the version of Ubuntu 16.04 LTS and other distributions are installed without such problems. Please tell me what to do?

When I'm  trying to install Ubuntu 18.04 on my desktop, it shows the following error:         The 'grub-efi-amd64-signed' package failed to install into /target/. Without the GRUB bootloader, the installed system will not boot.   How to fix this error?


I've been trying to update my iPhone to iOS13.5.1. I couldn't find an option to update via Mobile Data (and apparently it's not supported), so I tried to create a hotspot through another phone and update my iPhone over that. However, it is not updating. Is there a workaround for this? Can I somehow lead my iPhone to believe that the mobile hotspot is a WiFi connection? PS: In the settings corresponding to the network, I've set Low Data Mode to off.

I can see that iTunes and App Store has in Settings to not automatically download updates.  But what about iOS updates themselves? The recent iOS 11.3 update for example, is near 800MB, and when I use my main phone as a hotspot, then will my other iPhone silently download the iOS update?  The issue is important because the 800MB can cost up to US$12 at $15 per GB such as on Verizon, meaning that to download the update from iOS 11.2.6 to 11.3, it can cost me $12, and if 2 secondary phones, that means US$24 for downloading an update I wasn't aware of.


I  want to obtain fig1 exactly of 4 by 3 inch sized, and in tiff format correcting the program below: import matplotlib.pyplot as plt  list1 = [3,4,5,6,9,12] list2 = [8,12,14,15,17,20]  plt.plot(list1, list2) plt.savefig('fig1.png', dpi = 300) plt.close()

How do you change the size of figure drawn with Matplotlib?


Hello Fellow Ubuntu users,   sudo apt-get update    on ubuntu 14.04 it keeps saying:  E: Malformed line 10 in source list /etc/apt/sources.list (type) E: The list of sources could not be read.   Please help me it has been like this for a while now and I just found this website. Thanks!

I have unistalled and reinstalled the Ubuntu Software Center as per info I found in a similar thread and I got the same response about line 91 or something like that.  I just tried to upload a screen shot but since I'm new it won't allow me to.  I also can not figure out how to cut and paste anything so I have to hand type what the error screen says, both when I attempt to open the software center and nothing happens, when I try to enter commands into the terminal to uninstall, reinstall, whatever I get the same following:  COULD NOT INTITIALIZE THE PACKAGE INFORMATION An unresolvable problem occured while initializing the package information Please report t:his bug against the 'update-manager' package and include the following error message: 'E: Malformed line 91 in source list/etc/apt/sources.list (dist parse)  E: The list of sources could not be read.,  E: The package list of status file could not be parsed or opened.   How do I report bugs?  What can be done about this.  I have searched and everything everyone says to do leads me back to the same line error message.  So, I don't know how to get to line 91 in the source list; to tell you what it says. Sorry, I'm really new to this. That is what I need is to find out how to get there and fix what it says. I would really like to NOT have to re partition my hard drive and start from scratch, so I'm really looking forward to getting this problem solved. I need to be able to install new software.


How do you explain a significant variable (p-value less than 0.05) in a linear regression equation in layman terms?

After taking a statistics course and then trying to help fellow students, I noticed one subject that inspires much head-desk banging is interpreting the results of statistical hypothesis tests.  It seems that students easily learn how to perform the calculations required by a given test but get hung up on interpreting the results.  Many computerized tools report test results in terms of "p values" or "t values".  How would you explain the following points to college students taking their first course in statistics:   What does a "p-value" mean in relation to the hypothesis being tested?  Are there cases when one should be looking for a high p-value or a low p-value? What is the relationship between a p-value and a t-value?


I have a Rapid Pulser connected to a Command Block, coordinates to the middle of nowhere, and when I get even 300 blocks close to it, it warps me to the coordinates. How can I destroy these blocks without getting close?

I set a command block to /tp. It was supposed to activate only if you had 0 time left, and to activate the command block with a hopper clock to keep giving it power.   But it is not checking if you have 0 time left, so it keeps teleporting me. I can't get close enough to the command block to break it, so I'm stuck in a neverending teleport loop.  Any ideas?


Here is my code  mysql_connect('localhost', 'root', 'password'); mysql_select_db('db'); mysql_query("INSERT INTO metabase(url, title, image, description) VALUES('http://www.imgur.com/', '$title', '$image', '$descr')") or die();   It does not show any error but the values are not inserted in database. My table name is metabase. url, title, images are varchar(255) and description text. This is the error  You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 's visual storytelling community. Explore, share, and discuss the best visual sto' at line 1   This is the description  The Internet's visual storytelling community. Explore, share, and discuss the best visual stories the Internet has to offer.   So it is because of ' how do i correct it?

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


In the past, I've managed to get the virtual box shared folder via the command on trusty and xenial boxes.  $ sudo apt-get install virtualbox-guest-utils   But now on the bionic version - the packages does not even exist yet.  So my question is, how do we share the folder on ubuntu 18.04?

I keep seeing places refer to the "multiverse" repository as a place I can get software, how can I enable this repository? Please specify how to do this graphically and via command line.


I have a string similar to this, this string is from a long HTML page source:  "entity_id":"1234567890"   I'm trying to parse the number 1234567890 like this, but the id could not be parsed:  var re = new Regex("\"entity_id\":\"([0 - 9] +)\""); var match = re.Match(task.Result);  var id = match.Success ? match.Value : string.Empty; Console.WriteLine(id);   Why it it's not parsed and how to fix it?

Say I have the string "User Name:firstname.surname" contained in a larger string how can I use a regular expression to just get the firstname.surname part?  Every method i have tried returns the string "User Name:firstname.surname" then I have to do a string replace on "User Name:" to an empty string.  Could back references be of use here?  Edit:  The longer string could contain "Account Name: firstname.surname" hence why I want to match the "User Name:" part of the string aswell to just get that value.


If we consider two objects of masses $m$ separated by a distance $r$, and the potential at infinity is assumed to be zero, then $-Gmm/r$ is the potential energy. But is it of the system or of the individual objects? Also, suppose we were to apply conservation of mechanical energy, if the objects are released, then would we use gravitational potential energy of both the objects separately in our equations?  Also, when we say potential at infinity is zero, what do we mean exactly?

I know that potential energy exists for a system of objects. But why? Is there no potential energy for a single object system? I assume that there is.  Consider the earth-object system. Suppose an external force lifts the object above the earth. Then the work done by it gets stored in the earth-object system as potential energy.Right?  Now, my question is that is the potential energy always zero for a single object system.   MY REASONING  If we consider the object only as the system and lift it above the Earth, we are doing positive work on it and filling it with energy and the gravitational field of the Earth is doing negative work on it and draining it of energy. Thus whenever the object is moving it has kinetic energy which is fine. But when it is not moving,i.e. when its weight is equal to the force applied by us, the net work done is zero and so the object should not have any kinetic energy. Does it have potential energy?


Evaluate $\int x^3 \sqrt{4-x^2} dx$  Is my solution correct? In the book, some other (final)solution is given.

$$\int x^3\sqrt{4-x^2}dx$$ I tried changing the expression like this: $$\int x^3\sqrt{2^2-x^2}dx=\int x^3\sqrt{(2-x)(2+x)}dx$$ And that's where I got stuck. I tried integration by parts but it doesn't simplify the expression.


For beta sites exclusively, the opened achievements tab will be overlapped by the "Next Privilege" box on a user's own activity page:    The above was took with Language Learning Stack Exchange open though I have reproduced in:   Retrocomputing Stack Exchange (beta) Coffee Stack Exchange (beta) PPCG (beta)   Can we not have the next privilege overlapping the Achievements tab (when opened)?

I know I'm late with this; this could be the last bug report about the old topbar. But the text on the privilege progress indicator (on your profile page) appears above the dropdown menu coming from the Stack Exchange button, as can be seen in the picture below.     Changing the z-index property of .s-progress-bar._badge .-info, .s-progress-bar._privilege .-info from 2 to 1 solves the problem.    The new menu seems to have a high enough z-index so that this is no longer a problem anymore:


Which one is correct and why? Please answer my question.

I want to know about the position of always in different sentences. For example:      Always she is tidy and on time.   Is it correct or not?


I'm sure this is for most of you a basic question, but it really puzzles me:  How it is that, even though all materials expand as they get warmer, and contract (maybe these are not the correct terms) when get colder, water exapands when freezes.  Thanks a lot.

One of the wonderful properties of water (as my high school biology teacher would say) is that in its solid form, it is lighter than its liquid form. This means that when temperatures drop below 0 degrees Celsius, the top layer of water on, say, a lake freezes first. This works out pretty well for any fish or other aquatic creatures living underneath, because the lower layers of water will not freeze.  I know that this is an exception to the general rule of solid and liquid states: A given substance, when transformed into its solid state, will generally sink in a container of its liquid state. My question is this: What other substances are exceptions to this rule (if any?). What features do they share with water that are responsible for this?


I've been trying to help my son with what seems an innocent enough equation, but I have to admit, I'm struggling and walking in circles - the question is: If $\frac{a}{b+c}+\frac{b}{a+c}+\frac{c}{a+b}=4$, what is $abc$? First I multiply both sides with the denominators: $a(a+c)(a+b)+b(b+c)(a+b)+c(b+c)(a+c)=4(a+b)(a+b)(b+c)$ $\Updownarrow$ $a^3+b^3+c^3=3(abc+a^2b+ab^2+b^2c+a^2c+ac^2+bc^2)$ From here I begin to run in circles - substituting $x=abc$ and expressing $a$, $b$ and $c$ in terms of $x$, for example, ends up after a while back at the beginning. So what is the trick - or is there no simple solution? (Sorry about the tag - I couldn't find anything more suitable for such an elementary question) Edit The suggested duplicate is not a full answer, I think. My question concerns the same equation, but the question is different, and the answers are only partial. I will accept the answer given by Rhys Hughes, since it answers my question and gives a good explanation of how he reached it.

If I had a very shallow question, then I am sorry. $x,y,z\in\mathbb{N}^{+}$ and$$\frac{x}{y+z}+\frac{y}{x+z}+\frac{z}{y+x}=4$$find $x,y,z$.  I try with AM-GM, just get$$ \frac{x}{y+z}+\frac{y}{x+z}+\frac{z}{y+x}\geq\frac{3}{2}$$  This means that the equation must have a real solution, but can not be sure there is an integer solution.  Let: $x=ay=abz$, then the equation becomes:$$\frac{ab}{a+b}+\frac{b}{ab+1}+\frac{1}{a^2+ab}=4$$  Which makes the problem become non-homogeneous, and seems to become more difficult. I have no more ideas. Could anyone help me? Thanks a lot.


I try to resfresh a div without refresh a full page. the code :    $(document).ready(function() {   $(".ext").on('click',function(event) {     var url = $(this).prop('href');     $("#change").load(url);     event.preventDefault();   }); });  page 1 page 2
   page 3   page 4
     for resfresh page1 and page2 no problem. But when I want to resfresh page3 and page 4 all page is resfreshing. I don't find the solution. Can' you help me?  ps : sorry, I'am french and my language is bad.

I have a bit of code where I am looping through all the select boxes on a page and binding a .hover event to them to do a bit of twiddling with their width on mouse on/off.  This happens on page ready and works just fine.  The problem I have is that any select boxes I add via Ajax or DOM after the initial loop won't have the event bound.  I have found this plugin (), but before I add another 5k to my pages with a plugin, I want to see if anyone knows a way to do this, either with jQuery directly or by another option.


i'm trying to use the  package  \usepackage{titlepages}   but TeX Maker gives me this error:     ! LaTeX Error: File `titlepages.sty' not found. Type X to quit or    to proceed, or enter new name. (Default extension: sty)   On Ubuntu 16.04, i install the following but the error still happens:  sudo apt-get install texlive   Please help.

I need to install a new TeX/LaTeX/ConTeXt package on my computer.  I'm running Ubuntu/Fedora/Slackware/Some-Version-Of Linux.  What are the possible ways to do this?    Note:   We get a number of questions that essentially reduce to this one; it was felt a good idea to have one question-and-answer that can cover all the standard methods.  See  for the discussion.  The question-and-answer are CW so that more information can be easily added.  If you have information to add, please do so.  If you are unsure, leave a comment here or (preferably) in .  Comments on the question and answer will be periodically removed to ensure that the information is clear.


The BQ Aquaris E4.5 Ubuntu Edition is the only official Ubuntu smartphone currently. Are there plans to enlarge the product palette to include other BQ devices (I'm especially interested in the Aquaris E6) or other smartphones in general.  I know that the first attempt to collection funding for an Ubuntu smartphone failed dramatically, but now that the flashsales of the E4.5 were a success, there might be some news I missed. Following BQ on Twitter in a non-English language is kind of annoying...

Canonical has recently announced , which is Ubuntu with a specific interface for mobile devices.  Where can I get phones with this version of Ubuntu pre-installed? If no devices are available yet, where can I pre-order one?


I started using a system that has sat dormant for about a year, so unfortunately some of the setup details are a little hazy. Grub is loaded with 1 instance of Ubuntu 14 inside the grub loader. This instance can only see about 4GB of the much larger (~200+GB) drive. I think this means the entirety of the grub partition is only 4GB.  There is a second instance of Ubuntu, this time Ubuntu 16 on the PC. When it boots up it does not go through the Grub dialogue. It also has access to much more of the hard drive (Don't have the exact number, but well over 150GB).  When the computer boots up I arbitrarily get grub->14 or 16. It used to be I mostly got 16 which was fine, it has all the work I do. Occasionally it would boot grub->14 which has no work and is basically a blank install on a small drive. I would reboot and again end up at 16. Not ideal but I'm lazy, don't reboot much, and it was workable. However recently 16 did an updated, needed a reboot and now it's only booting grub-14.  Based on the behavior above I believe 16 and grub are logical siblings when grub should be a logical parent of ANY operating system on the machine.  I'm looking for options to dig myself out of this hole. A complete reinstall is an option but not preferred. I don't have a problem blowing away the grub->14 partition as it was a failure. I am interested in what if any are my options in getting 16 inside a grub control after the fact.  Edit1: There is a comment suggesting a grub update and a duplicate flag indicating the same. I ran grub update grub 2 update both with reboots. No difference in behavior. Is there a configuration file that needs a new entry? If so do I need to indicate the location of the missing OS? How would I find out such a thing?  Edit2: I ran lsblk and sudo parted -l to get the following. Apologies for the screenshot. The 14 install doesn't have the right network card drivers for connectivity to copy/paste.     Edit 3:pvdisplay produces the following    Eldergeek asked the following in the comments:     Just so I'm clear, you installed Ubuntu 14.04 on one drive and 16.04 on the other within hours of each other?    No, originally I installed 2 copies of 14.04. I think my plan was to put the bootable details on the faster of the two drives. I mixed them up and did a second install on the otber drive, That was recently upgraded to 16.04 shortly before I lost all access to that install. If I prioritize that drive I get a grub rescue prompt. I believe this is a new development, not positive though.      The intention is to boot the 16.04 Ubuntu and provide additional space for that.    Yes     The 14.04 Ubuntu is unimportant   Yes

I went into Live CD and activated Terminal.  Then, I typed gksu nautilus to gain temporary access to my root directory. Once the Manager window opened, I clicked on File System and navigated to the /etc/default/grub directory. I then double clicked on the Grub file to make changes to the TIMEOUT and TIMEOUT_QUIET.  I saved the file after I made the changes. Then I went back to the terminal mode and typed:  gksu update-grub   The error message I got was:     Can not find a device for / (is /dev mounted?)   I'm not sure what to do at this point. How can I run update-grub to update the changes? Thanks in advance for your help. Please be very detailed and specific with your response as I am totally new to this environment.


I am trying to include a background image in a tikz/pgf drawing. I need to be able to draw nodes directly on certain features of the image, it thus needs to be precisely adjusted.  This would be easiest if I could somehow fix it to two nodes defining the corners of the image, like so:   \documentclass{article} \usepackage{pgf,tikz} \begin{document} \begin{tikzpicture} \node at (0,0) {a}; \includegraphics{something.png} \node at (2,2) {b}; \end{tikzpicture} \end{document}   Of course this does not do what I want, i.e. scaling the image so that it its top-right corner is at (2,2) and the bottom-left corner at (0,0):

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


I would like to cite a paper by Bibtex. The bib entry is  @Article(Zolandek2007, title = {The {PF030405a} {‘‘Krzeszowice’’} fireball}, author = {P. {\.{Z}}o{\l}\c{a}dek and A. Olech and M. Wi\'{s}niewski and M. Kwinta}, journal = {Earth, Moon, and Planets}, year = {2007}, volume = {100}, number = {3--4}, pages = {215--224}, file =        f )   Bibtex omits the dot between \ and {Z}, so the entry in bbl file looks like this:  \bibitem[{\.{Z}o{\l}\c{a}dek et~al(2007)\.{Z}o{\l}\c{a}dek, Olech,   Wi\'{s}niewski, and Kwinta}]{Zolandek2007} \{Z}o{\l}\c{a}dek P, Olech A, Wi\'{s}niewski M, Kwinta M (2007) The {PF030405a}   {‘‘Krzeszowice’’} fireball. Earth, Moon, and Planets 100(3--4):215--224   LaTeX then announces error Extra }. If I finish translation in spite of it, the result      {Zołądek P, Olech A, Wiśniewski M, Kwinta M (2007) The PF030405a   Krzes- zowice fireball. Earth, Moon, and Planets 100(3–4):215–224   begins with a wrong brace, the dot above Z is missing and also quotation marks around word Krzeszowice are missing. Does anybody have any advice, how to cite papers with so complicated names?     I have read the answers to the question "How to write “ä” and other umlauts and accented letters in bibliography?" I have tried all the characters proposed there:  {\"a}{\^e}{\`i}{\.I}{\o}{\'u}{\aa}{\c c}{\u g}{\l}{\~n}{\H o}{\v r}{\ss}.   Everything works except {\.I}. After Bibtex, the dot is off and LaTeX does not know the order \I.   I use these documentclass and packages:  \documentclass[smallextended]{svjour3} \usepackage{graphicx} \usepackage{amsmath} \usepackage{multirow} \usepackage{natbib} \usepackage{color} \usepackage{tikz} \usetikzlibrary{shapes.geometric, arrows, calc}   The natbib package could theoretically influence it, but it works by the same way both with and without natbib.

How to write in bibliography (package natbib) letter "a" with two dots above? Specially, I mean the word Birkhäuser.  Is there a general rule or way how to write such umlauts or other accented letters in bibliographies?


I am looking to host lidar data on my own server and give clients the ability to view that data through a web browser as a 3D point cloud (file would be in .las format or equivalent), possibly with the ability to measure features.   Does anyone know of an easy to implement piece of software that can do this?  I am not nessecarily looking for open source, and I would prefer something plug and play because I am not a programmer.

I have lidar data which I want deploy my users using web viewer.  I will probably hold the data in PostGIS (not sure yet).  Is there good open source/free lidar viewer that I can integrate with OpenLayers site?


My phone's power button is messed up. So am looking for something which will help me lock my phone and turn it on using either tapping or sliding. The knock lock app is great for locking but doesn't wake the phone. Is there an app/something that I can install that will help me lock/unlock without using my phones power button ?   Details :  Android version : 4.4.4  Phone : Nexus 4 Although I dont know the pros and cons yet but I don't want to root my phone

The power button on my Nexus One doesnt work smoothly any more, sometimes taking nearly half a dozen attempts before the unlock screen appears on the phone. I was wondering is there is any other way to invoke the unlock screen on my phone, apart from pressing the power button. I have Gingerbread 2.3.4 on my phone.


when I do a command such as ps -aux on CentOS 6 I get a bunch of processes whos command is listed in [] as shown below. What is the meaning of the [] in the name? I am assuming that these are special processes of some kind, what makes a process name show up with  a [] around it?   [root@centos6 src]# ps -ef UID        PID  PPID  C STIME TTY          TIME CMD root         1     0  0 18:48 ?        00:00:01 /sbin/init root         2     0  0 18:48 ?        00:00:00 [kthreadd] root         3     2  0 18:48 ?        00:00:00 [migration/0] root         4     2  0 18:48 ?        00:00:00 [ksoftirqd/0] root         5     2  0 18:48 ?        00:00:00 [migration/0] root         6     2  0 18:48 ?        00:00:00 [watchdog/0] root         7     2  0 18:48 ?        00:00:02 [events/0]

$ ps -Awwo pid,comm,args   PID COMMAND         COMMAND     1 init            /sbin/init     2 kthreadd        [kthreadd]     3 ksoftirqd/0     [ksoftirqd/0]     5 kworker/u:0     [kworker/u:0]     6 migration/0     [migration/0]     7 cpuset          [cpuset]     8 khelper         [khelper]     9 netns           [netns]    10 sync_supers     [sync_supers]    11 bdi-default     [bdi-default]    12 kintegrityd     [kintegrityd]    13 kblockd         [kblockd]    14 kacpid          [kacpid]    15 kacpi_notify    [kacpi_notify]    16 kacpi_hotplug   [kacpi_hotplug]    17 ata_sff         [ata_sff]    18 khubd           [khubd]   What do the brackets mean? Does args always return the full path to the process command (e.g. /bin/cat)?


It is well-known that if $p$ is a prime of the form $4k+3$ and $p|x^2+y^2$ then $p|x$ and $p|y$. I forget what is the name of this result, and where can I find a proof (please provide a link).

Let $u$ be an integer of the form $4n+3$, where $n$ is a positive integer. Can we find integers $a$ and $b$ such that $u = a^2 + b^2$? If not, how to establish this for a fact?


I'm searching how to tag two Players using one /testfor command. I'm actually using this command which works for one person :  /testfor @a[name=!<pseudo>,r=15]   But it doesn't work for two Players. Is it possible?

I've asked this question towards a developer for Minecraft and I thought I'd ask here too since they might not see the question.  How do I select all but two types of entities in Minecraft?  For example, something like: /say @e[type=![Player,Item],r=50] (to clarify I also tried type=Item,Player, type=Item,type=Player etc)  Should select any entity that does not match players or items, so things like Creepers, Ghasts, XPOrbs, PrimedTNT and so on within a radius of 50 blocks and print them to the chat.  Instead it ignores one of the flags, and works with the other instead.


WHY is eevee not supported ? A few days ago new versions of Blender supported it. But suddenly it disappeared (under eevee or viewport shading)

I don't know why but now, when i go in material preview or rendered (in solid mode it works fine), my object is entirely gray, or invisible idk, because it has the same color of the background. I've been working for days on this project without having this issue, it suddenly showed up. I tried opening other old projects and suddenly they all do the same so i guess it is some blender program setting that applies for all the projects, but idk how it happened cuz i didn't change anything :/, anyone got any tips?


I have a code to add content to my custom columns, that looks like this  add_action( 'manage_posts_custom_column', 'my_custom_columns', 10, 2 );     function my_custom_columns( $column, $post_id ) {     switch ( $column ) {         case 'column1':         echo 'output1';         break;         case 'column2':         echo 'output2';         break;         case 'column3':         echo 'output3';         break;     } }   There is a way to do the same thing with default columns like the Title one?

Here is my situation: I am trying to filter the content of the title column in my custom post type edit table but I can't get it working.   Here is what I have tried:  add_filter('manage_edit-mycpt_columns', 'replace_title_products');  function replace_title_products() {     $oldtitle = get_the_title();     $newtitle = str_replace(array("", ""), array("", ""),$oldtitle);     $title = esc_attr($newtitle);     return $title;   }   I just want to filter the  tags in my title. Could someone help me please?


Player A and B both have equal chance of winning any given point regardless of who's serving, so there is a 0.5 probability for either of them to win any point and therefore the game. My question is if Player A wins the first point and goes 15-0 up (as per the tennis scoring system) what are their chances of winning the game? Also what about if Player A is 30-15 up, or 40-15 up?  Thanks for any help, James

Suppose there is a tennis singles match, where Player A plays a single game against Player B.  The probability that player A will win a single point is $x$, and thus $1-x$ is the probability that Player B will win a point.  The scoring system in tennis goes 15, 30, 40, then game.  However a score of 40-40 is known as deuce and the winner of the next point gains an "advantage".  If this player wins again, he then wins the game, but if he loses the score returns to 40-40, or deuce.  So given the probability player A will win a single point is $x$, what is the probabilty that player A will win the entire game?


I'm have windows 10. I'm can print colored text in windows without any module? (like colorama) if I run: GREEN =  '\033[32m'  print (GREEN + "This is some green text!")  then I got ←[32mThis is some green text! why?

How can I output colored text to the terminal in Python?


How Can I get the Process information of the process which is holding apt-get lock?

I want to know the exact process that is using the lock file. I don't want to fix it, but just to know what is my system doing. How can I find out?  For example, this message:  E: Could not get lock /var/lib/dpkg/lock - open (11: Resource temporarily unavailable) E: Unable to lock the administration directory (/var/lib/dpkg/), is another process using it?   Again, I just want to identify the process using it, not how to fix it.


Original code:  if (!externals.containsKey(query.getName())) {   I need to check also if query.getName() != "manualPrice" so my code becomes:  if ((!externals.containsKey(query.getName())) && (query.getName() != "manualPrice")) {   this isn't giving me the desired result. I'm not getting errors but the page isnt loading.  However annoyingly enough this code does work (it just doesnt feel as neat):  if (!externals.containsKey(query.getName())) {   if (query.getName() != "manualPrice") {   is there something really obvious I'm missing out. Im not normally at Java developer but do know C# which is pretty similar from what I've seen. Im hoping its just something silly I've missed.  cheers  UPDATE *****  ok so people have pointed out that rather than == i should be using .equals  which I have done. my new code is:  if ((!externals.containsKey(query.getName())) && (!query.getName().equals("manualPrice"))) {   which still gives the same error as it did with the ==  I'm begrudgingly using the nested if method for now but its just got me baffled as to what could possibly be wrong with it. It compiles fine!

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


I have a HP Mini110 1030NA with an Atom N270 1.60 GHz and 1 gig of RAM.  Currently running XP with no issues other than not much can be used with XP anymore.  What version of Ubuntu will work on it if the XP is removed, and can I download that onto a Sandisk Cruzer or similar USB stick?  I still have 127GB of hard drive left even with XP still on there.

For a given hardware configuration, how do I find out if Ubuntu will run on it? What considerations should I take into account when choosing an Ubuntu version and  such as:    with a lighter desktop than the usual Gnome and Unity  with the even lighter LXDE desktop   Obviously Ubuntu does not run on some processor architectures. So how do I go about choosing the right version and derivate. How can I find out the minmal system requirements?


Here is my code for generate combobox. How can I add a css class name 'chosen-select' on it ?     var cell3 = row.insertCell(2);     var element2 = document.createElement("select");     var option1 = document.createElement("option");    option1.value="";    option1.innerHTML="--Select--";       element2.appendChild(option1);     var option2 = document.createElement("option");    option2.value="1";    option2.innerHTML="Apple";      element2.appendChild(option2);     element2.name = "description" + rowno;   element2.id = "description" + rowno;    element2.setAttribute("required","true");    element2.style.width = "150px";    cell3.appendChild(element2);

How can I change the class of an HTML element in response to an onclick or any other events using JavaScript?


I have an image of a scene and I extracted the projection matrix from that, so I have the camera calibration. Now, I want to add some 3D objects to this scene. I have already coded something with OpenGL. You can see the results here (the white wall is added in OpenGL):    Now, I want to achieve the same thing with Blender, because it's easier to work with complex models and complex scenes. Can anyone give me any pointers on how to convert from OpenGL camera to Blender?

I was wondering how you would go about putting a 3D object into a photograph so that portions of the image are:   In front of, or Behind the model.   For example, a photo taken from the roadside with a tree in the foreground.  I want to show a 3D model of a car in the photo on the road but a section of it is not visible because it is obscured by the tree.  Is this possible? If so, how can you do it?  Thanks in advance.


I just deleted  in response to a disputed review flag:    After seeing the deleted-by label, I assumed that review had somehow beaten me to the deletion.  disproves that:    It looks like the deletion label on the post is picking up on the later timestamp, but the earlier deleters. Looks like a bug.

I found  (only visible to 10k+ users on SFF, sorry) which had been deleted from review some hours ago but also flagged for conversion to a comment. I undeleted it and converted it to a comment (which of course re-deletes the answer), only to see that the post claimed to have been "deleted from review just now" by the same list of users as before.  Here's a screenshot of the timeline:    And here's one of what the post itself looks like now:    It was actually deleted from review 3 hours ago and then undeleted and redeleted by me 36 minutes ago, but to a casual observer it looks like it was deleted from review 36 minutes ago.  I'm posting this as a  report because it's technically showing incorrect information, but I'd be perfectly happy to be told it's actually a new feature. In fact, I've often found it annoying that when a whole bunch of users have voted to delete a post and then I convert it to a comment, their votes don't show up and it looks like I've acted unilaterally to remove it. This kind of remedies that.


I am looking for a word that would describe a concept or activity, such as playing a game X, that is1 neither boring nor interesting. In other words, it should mean ‘neutral’ wrt intrestingness (~ boringness) but still comparable on the scale of intrestingness to both ‘boring’ and ‘interesting’.  An example sentence would be  As far as I'm concerned, long-distance running is [insert word]; it is not boring but it's also not interesting.  Criteria2   Has to be unambiguous3, and may consist of two words at most. Has to be a single word. Should be formal in the sense that it is included in Cambridge Dictionary, or Merriam Webster, or both. Should not contain negating prefixes, such as ‘un-’.   Does such a word exist in the English language?  For readers' convenience, please state which criteria you believe your word suggestion has met. You may do so, e.g., by adding a disclaimer at the top or bottom of your answer. Simply writing (1., 2.) is sufficient.        1 Assume a ternary system of intrestingness.   2 If not all criteria can be met, you may relax  the requirements from bottom to top, in the following order: 4. -> 3.  -> 2. -> 1. Answers with the smallest number of relaxed criteria in this order will be preferred in accepting. For example, fulfilling  (1., 2., 3.) is better than achieving (1., 3., 4.). Situations where a  higher priority ordering fulfills fewer criteria than a lower priority  vector, such as (1.) vs (3.,  4.), will be assessed on a case-by-case  basis.   3 Words such as ‘unappealing’ thus even fail  criterium 1 because in a three-valued system ‘unappealing’ ~ ‘not  appealing’ ~ ‘not interesting’ can be taken to mean either ‘boring’ or  ‘neutral wrt intrestingness’.

I'm trying to find a word for something meaning not explosively popular or successful, yet not a failure. It should not be intended as criticism and should represent something not necessarily new but more forthcoming or predicted to be destined for eventual greatness.     Alphie's _______ novel Xyz is a ....


From      For directories, the execute permission is a little different; it means you can do things to files within that directory (e. g. read or execute them).   cd into a directory needs execution permission, but does it do something to some file in the directory, and if yes, how? The best I can think of is cd do something to the file . under the directory, but why doesn't cd just deal with the directory itself, instead of any file under it, so as to avoid needing execution permission?  Thanks.

In my CMS, I noticed that directories need the executable bit (+x) set for the user to open them. Why is the execute permission required to read a directory, and how do directory permissions in Linux work?


Can the taxonomist badge be awarded more than once?   I would think so, but there are only 874 badges awarded and over 1500 tags that have been used 50+ times.  The definition states "Created a tag used by 50 questions"

Formerly List of all badges with full descriptions.  What are badge name's requirements? Why didn't I get badge name ? Which badges can I earn multiple times?    Jump to:                    Note: Some badges are awarded based on score. The term score means the total number of upvotes minus the total number of downvotes.  Any badge with a *** next to it is one of 20 badges that count towards the  displayed on a moderator candidate in an election. The candidate score is a total of 40 points: the first 20 are awarded based on the user's rep divided by 1000 and rounded down; the second 20 represents the total number of unique badges earned of the 20 that count. Note that if the same badge is earned multiple times, it will only count once towards the candidate score.  Any badge with a "(retired)" next to it is no longer awarded, but is retained by users who previously earned them. See  for more info on what it means for a badge to be retired.       Visit the  of the  on any site to see a complete list of badges that you can filter by earned, unearned, or type.


I'm currently learning polymorphism in Java, and part of the assignment was to create a program that will print out various subclasses using inheritance and polymorphism. I have tried looking for solutions but I couldn't seem to find anyone else experiencing this issue.  Below is a piece of code that is supposed to print Alex and Alexa respectively. However, the output is, instead, Alexa Alexa.  I have tried debugging by stepping through using Eclipse, but I can't pinpoint what is the mistake. I am truly stumped at this point, I've been trying this question for the past week but to no avail. Please forgive me if this is a simple question but I can't figure out what went wrong. I would truly appreciate any assistance!  import java.util.ArrayList; public class Human {    protected static String name;     public Human(String name) {        System.out.println("In human constructor");        this.name = name;    }    void greetings() {}     static void print(Human human) {        System.out.println(name);    }     public static void main(String[] args) {        ArrayList<Human> human = new ArrayList<Human>();        human.add(new Man("Alex"));        human.add(new Woman("Alexa"));        for (int i = 0; i < human.size(); i++) {            print(human.get(i));        }    } }  class Man extends Human {     public Man(String name) {        super(name);        // TODO Auto-generated constructor stub    }  }  class Woman extends Human {     public Woman(String name) {        super(name);        // TODO Auto-generated constructor stub    }  }

To be specific, I was trying this code:  package hello;  public class Hello {      Clock clock = new Clock();      public static void main(String args[]) {         clock.sayTime();     } }   But it gave the error      Cannot access non-static field in static method main   So I changed the declaration of clock to this:  static Clock clock = new Clock();   And it worked. What does it mean to put that keyword before the declaration? What exactly will it do and/or restrict in terms of what can be done to that object?


I have been trying to use the /give command to give a named book, but I can't seem to give it. I keep on getting the error message of:  Line 1, Column 2 Missing '}' or object member name.  What am I doing wrong?

This question was recently split into different questions for each workaround. See   meta posts for more information.   Can you use NBT tags in commands? I’ve tried commands that normally work in Java Edition like: give @s minecraft:planks 30 1 {display:{Lore:["Wooden planks"]}} give @s stone_pickaxe{Unbreakable:1b} give @s item_frame{EntityTag:{Invisible:1b}} summon villager ~ ~ ~ {Offers:{Recipes:[{buy:{id:"emerald",Count:5b},sell:{id:"diamond_sword"}}]}} summon tnt ~ ~ ~ {Fuse:20s}


I am scraping a site using phantomjs and receiving a response in this encoding and it is after converting to utf8: "\x1Fï¿½\x8\x3ï¿½ï¿½ï¿½ï¿½ã¶‘(ï¿½ï¿½ï¿½Wpï¿½gï¿½ï¿½ï¿½E\xE\x1Fï¿½\x1Eï¿½;>k;ï¿½zoï¿½lNï¿½ï¿½ï¿½\ß¹s(ï¿½jï¿½C=ï¿½TOï¿½ï¿½ï¿½ï¿½ï¿½(<h< ï¿½\x19ï¿½fï¿½ï¿½q<-\x1ï¿½ï¿½bï¿½ï¿½\x2="" @ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½~ï¿½ï¿½ï¿½ï¿½ï¿½7ï¿½ï¿½ï¿½="" ï¿½ï¿½<ï¿½ï¿½ï¿½ï¿½^ï¿½\x1Dï¿½ß¾(\xE="" ï¿½ï¿½"[ï¿½ï¿½ï¿½4g_ï¿½3="" ï¿½fu]ï¿½ß¾ï¿½ËŸï¿½="" ï¿½ï¿½\x1Dï¿½!ï¿½\x17o_|ï¿½\x15ï¿½ï¿½cu~ï¿½ï¿½ï¿½Ã¹8ï¿½"\xFuqï¿½uï¿½ï¿½Ùª,ï¿½\x1Eï¿½\x13ï¿½qï¿½="">oß®ï¿½ï¿½ï¿½ï¿½ï¿½é�‰ï¿½;ï¿½Î»ï¿½ï¿½ï¿½ï¿½ï¿½(\x8'ï¿½ï¿½'ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½\x1A5ï¿½ï¿½ï¿½ï¿½ï¿½Mv:ï¿½ï¿½ï¿½?ï¿½vï¿½ï¿½cï¿½ï¿½Iï¿½ï¿½g'ï¿½Dï¿½ï¿½ï¿½ï¿½" Any suggestions on how to convert it into a regular html string?

I'm setting up a new server and want to support UTF-8 fully in my web application. I have tried this in the past on existing servers and always seem to end up having to fall back to ISO-8859-1.  Where exactly do I need to set the encoding/charsets? I'm aware that I need to configure Apache, MySQL, and PHP to do this — is there some standard checklist I can follow, or perhaps troubleshoot where the mismatches occur?  This is for a new Linux server, running MySQL 5, PHP, 5 and Apache 2.


Here's my writeToFile() method:  public void writeToFile(String string){     x.format("%s", string); }   And this is how I use this method:  private class HandlerClass implements ActionListener{     public void actionPerformed(ActionEvent event){         string = tekstPole.getText();         tekstLabel.setText(string);         f.writeToFile(string);     } }   When I try to compile I get     Exception in thread "main" java.lang.NullPointerException       at Files.readFile(Files.java:30)       at Bicycle.(Bicycle.java:34)       at Hristijan.main(Hristijan.java:10)   What could be the problem?

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


Okay, studying Networking at university and I cannot remember the answer to a very simple question.  Can different subnet's have the same subnet mask?  IE Subnet 1 Range: 192.168.0.0 - 192.168.0.31 with a subnet mask of 255.255.255.224 Subnet 2 Range: 192.168.0.48 - 192.168.0.79 also with a subnet mask of 255.255.255.224  Are these two both valid subnets, or do the masks have to be different?  Thanks in advance!

This is a  about IPv4 Subnets.      Related:               How does Subnetting Work, and How do you do it by hand or in your head?  Can someone explain both conceptually and with several examples? Server Fault gets lots of subnetting homework questions, so we could use an answer to point them to on Server Fault itself.   If I have a network, how do I figure out how to split it up? If I am given a netmask, how do I know what the network Range is for it? Sometimes there is a slash followed by a number, what is that number? Sometimes there is a subnet mask, but also a wildcard mask, they seem like the same thing but they are different? Someone mentioned something about knowing binary for this?


I am from Italy and as such I have a 30bdays exemption visa to enter thailand. This will be valid until the 21st of February. Tomorrow 16th of February I will leave Thailand for Malaysia, but I plan to go back to Thailand on exactly the 21stand stay till the 28th of February. Will I get a new 30 days exemption permit, even if I am still within the limit of my previois permit?

On arrival in Bangkok airport, a Thai immigration officer instructed me that I have many previous visa exempt entries in Thailand, and will need a visa for the next time. However, I could not find any official information.  Is there any regulation limiting the number of visa exempt entries, their total duration, or anything of that kind? (I am a German citizen if that is of any importance.)


I've been following a course on creating a character with Blender 2.8 and have got to a point where I should make the helmet glass part look like glass. After applying the filters to do that, the hair on my character disappears. Do you know why that might be?  Filters for helmet glass    Filters for hair

I was just testing Eevee and found that you cannot view a glass object through another glass. Is there any workaround? It works fine only If I rotate the glass window or put my camera to the back side of the scene


Am not sure whether its just for me or the normal account users as well, but on this particular question, , buttons are wrapping up in two lines...    Am on Chrome Version 33.0.1750.5, Windows 7, 1366*768 Resolution.

If you go to  and are a 4k+ user on Anime.SE, you will see the following:        There is one reopen vote on this question, but the reopen vote count is displayed on a different line than the word "reopen". This is slightly silly, and would perhaps benefit from converting reopen (1) to reopen&nbsp;(1), and likewise for close and delete votes. (Or any other way of preventing a line break between the vote type and the vote count.)  A repro (the close link) from here on Meta:


My table is like this:  Sitecode    Month  Amount --------    -----  ------ XX          Jan     1000 XX          Jan     3000 XX          Apr     3000 XX          Apr     1000   What I want is, to show the result something like this:  Sitecode    MonthJAN   MonthAPR --------    --------   -------- XX          4000       4000


I tried to integrate this: $\displaystyle\int \dfrac{dx}{x^4+1}$  I tried to do it with the partial fractions method (after factoring the denominator), but the process is really large, and I got a lot of mistakes.  Is there another way to solve this?  Thanks in advance :)  P.S. I'd put what I did, but I don't have the papers anymore, sorry :(

Just doing this for revision, seems much harder than it should be, should I use $x=\tan u$ ? Any help appreciated.


I answered  question on SO.   Now I see that it got deleted - but the upvote count for the question shows +2. How is it possible that non-moderators would see the "delete" link ... that only shows up when the question shows -3 or more?  And beyond that: I think I read more than once that "question is a duplicate" doesn't translate to "question should be deleted". So isn't "positive reception" of question with answers an indication to not delete it?

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


I know that because of the birthday problem, even after 365 friends, you're going to have a lot of doubles and that there's also an infinitesimal chance that even with infinite friends that there's one day left out. But I was curious how many friends you'd need on average to have every day represented (this is ignoring leap day and assuming birthdays are equally distributed). Or to generalize it further, given n unique boxes and you're placing balls in them with an equal 1/n chance for the ball to go into any box, how many balls would you have to place on average before every box had at least one ball?

What is the average number of times it would it take to roll a fair 6-sided die and get all numbers on the die?  The order in which the numbers appear does not matter.  I had this questions explained to me by a professor (not math professor), but it was not clear in the explanation.  We were given the answer $(1-(\frac56)^n)^6 = .5$ or $n = 12.152$  Can someone please explain this to me, possibly with a link to a general topic?


I'm new to this but I have a question, when someone only tells you part of the truth for example a conversation:     Me: hey I bought a new car   Saying I bought a new car, but hiding the fact that its second hand. I remember someone telling me this and that the media does it. Is this shadowing or something?

The statement that inspired the question was "Newton was wrong [about the laws that govern movement]". Although some exceptions have been found to Newton's laws since he discovered them and thus the statement is true, the laws are still taught and used, making the statement misleading.  Another example would be "I've never lost at chess" when the speaker has never played a game of chess.


If you run a code snippet, a hat still appears. Steps to repro:  Go to a question where there is a snippet and where the OP wear a hat well, if you find that hard, just go here.  (BTW, it's my answer)  Then, run the snippet.      Or just see here:   Winter Bash 2020!

It seems like there is a bug that is causing a duplicate hat to appear when I expand info, like pressing "(more)" on a suggested edit. This bug does not seem to be specific to the suggested edits review queue though, as others have reported seeing this bug in other places, like code snippet expansion. Steps to repro:  Put on a hat. Navigate to one of your own suggested edits. (You can just also open the Suggested Edits review queue and go to a random suggestion, but there is no guarantee any of those users will be wearing a hat.) Click the "(more)" button to expand the top box.  What should happen: Hat should shift down with the rest of the content. What happens: All the content shifts down, but a duplicate hat remains in the initial place. Before expansion:  After expansion with duplicate hat:


I am using a Mac--which is running OS X 10.10.3. I want to add a 'new file' button to the context menu--the menu that pops up when you right-click in a Finder window/on the desktop.

When I right click anywhere I get an option to add a new file with a specified extension. I would like to add some custom files into this menu, so I can right click and create a new PHP file for instance.  How can I do this?


Hi I am trying to simulate the flow of water through a porous medium using ANNs. I have managed to get good result when the porous medium is homogeneous, however when it isn't the network seems to struggle to capture sharp changes in the water flow.  In the example below a change in the porous medium properties lead to a "kink" in the test data (obtain using standard numerical techniques in my field) which cannot be captured by my simple neural network.  The neural network has 2 inputs a distance x and a time t, 2 hidden layer with 7 neurons, and an output layer with 1 neuron. The weights and biases are randomly initialized between -1 and 1. I tried increasing the number of neurons in the hidden layer up to 80 without getting any better.  I was wondering what the next step should be, should I add more training data from around the boundaries of the kinked areas ? Should I add a few more hidden layers to my network ?      Thanks !

I'm training a neural network but the training loss doesn't decrease. How can I fix this?  I'm not asking about overfitting or regularization. I'm asking about how to solve the problem where my network's performance doesn't improve on the training set.    This question is intentionally general so that other questions about how to train a neural network can be closed as a duplicate of this one, with the attitude that "if you give a man a fish you feed him for a day, but if you teach a man to fish, you can feed him for the rest of his life." See this Meta thread for a discussion:   If your neural network does not generalize well, see:


Suddenly this question comes to mind when i saw a sticky-label faded, when compared to comparatively new one. So question here is does it simply fades away like physical particles or is there anything complex associated with it.

If you leave something outside, its colors seem to inevitably fade or bleach due to exposure. Is this due to UV absorption? What sort of mechanism causes this - is it that man-made dyes  deform on a molecular level? Are there notable materials that are exceptions?  To turn this string of questions into a focused query, let me refer back to the title:   Why does sunlight cause colors to fade?


I have checked for similar questions regarding the error however they didn't match the issue I seem to be having.  Getting the following error when attempting to insert data into database:     Column count doesn't match value count at row 1?   Here is a screenshot of the database table:   In the HTML a form, with an action of the php file, has multiple inputs with the names: name, surname, DateOfBirth, email, password, confirm-password  PHP:  <?php  // Only process the form if $_POST isn't empty if ( ! empty( $_POST ) ) {    // Connect to MySQL   $mysqli = new mysqli( 'localhost', 'root', '', 'pptpp' );    // Check our connection   if ( $mysqli->connect_error ) {     die( 'Connect Error: ' . $mysqli->connect_errno . ': ' . $mysqli->connect_error );   }    // Insert our data   $sql = "INSERT INTO user ( Forename, Surname, DateOfBirth, Email, Password ) VALUES ( '{$mysqli->real_escape_string($_POST['name, surname, DateOfBirth, email, password '])}' )";   $insert = $mysqli->query($sql);     // Print response from MySQL   if ( $insert ) {     echo "Success! Row ID: {$mysqli->insert_id}";   } else {     die("Error: {$mysqli->errno} : {$mysqli->error}");   }    // Close our connection   $mysqli->close(); }  ?>

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


Suppose that $R$ is a commutative ring with unity in which every maximal ideal is finitely generated. Then is $R$ Noetherian?

In commutative rings we have the following  Theorem. $R$ is Noetherian if and only if each prime ideal of $R$ is finitely generated.  From this Theorem I am looking for commutative rings $R$ in which every maximal ideal is finitely generated but $R$ is non Noetherian.  Question: Is there a straightforward example of a commutative ring $R$ so that each maximal ideal is finitely generated, but $R$ is non Noetherian?  Thank You


I've read about Fermat's little theorem and generally how congruence works. But I can't figure out how to work out these two:   $13^{100} \bmod 7$ $7^{100} \bmod 13$   I've also heard of this formula:  $$a \equiv b\pmod n \Rightarrow a^k \equiv b^k \pmod n $$  But I don't see how exactly to use that here, because from $13^1 \bmod 7$ I get 6, and $13^2 \bmod 7$ is 1. I'm unclear as to which one to raise to the kth power here (I'm assuming k = 100?)  Any hints or pointers in the right direction would be great.


How can I include in a (zsh) shell script a command that will minimize one particular window among several windows open in a specified app? I already know how to include a command that opens an app with one or more documents open in it, e.g.: open -a textedit.app .profile .zshrc  What command can I use from Terminal to minimize a specified one of those just-opened windows? I presume that something involving osascript is involved, such as in . But the method given there in the Edit by the original poster: (i) minimizes all the windows; and (ii) does use osascript which, as I recall, is not so simple to call from within a shell script.

I'm trying to make my discord bot console (running in terminal) minimize itself, but I do not know a command for minimizing. I tried looking around but I found nothing.


I wanted to show someone in chat a revision that someone did so I linked it to them:   But that just shows this:        Which has no data about the revision.  In order to see what has been revised one has to click on Return to Revisions, then go to revision 3 and then and only then do they see what was revised:          Can we please have some way to see what has been revised when going to a direct link of a revision?

Currently, the only way to link to a revision (clicking "link"), you just get  which shows what the post looked like at that revision:        Personally, I rarely use this and haven't ever found myself in a scenario (as far as I remember) where I would prefer the way it currently works to what I'm suggesting here.  Could we:   Add another link, or Change the current link   Such that it:   Displays the diff on a separate page (I'd prefer this, since the highlight and scroll thing doesn't always work properly - although perhaps it has something to do with loading images, so it might not apply here, or, if it doesn't, we could fix that instead), or          Highlights and scrolls to a diff, like what is done when you link to an answer ()


To notate the inverse hyperbolic functions, we may see two different prefixes: ar_ and arc_. The former stands for AREA, while the latter for ARC. Thus, the latter seems not reasonable, since it is likely to be a sort of false analogy with the notations for the inverse trigonometric functions.  But the famous website  just use the latter. Why is it? Just "Make the Same Mistake"?

I note that some people like to write the inverse hyperbolic functions not with the prefix "arc" (like regular inverse trigonometric functions), but rather "ar".  This is because the prefix "arc" (for arcus) is misleading, because unlike regular trigonometric functions, they are not used to find lengths (inverse trigonometric functions can be used to find arc length of ellipses like $x^2+y^2=1$) but rather find area of a sector of the unit hyperbola.  Which version should be preferred?  $\operatorname{arsinh}$ initially confused me as I did not know why "ar" was used.  However, some seem to prefer this notation as it is more of an accurate description of the function.


I'm using CLion 2017.2.3 and there is an error by its Intellisense saying Return type of function 'func' differs... (Image attached below). Isn't the default return type in C++ int? And why is the IDE showing it as an error? Is it a bug?  EDIT: It compiles and runs fine(without any flags, doesn't with them)

In C the following horror is valid:  myFunc() {   return 42;  // return type defaults to int. }   But, what about in C++? I can't find a reference to it either way...  My compiler (Codegear C++Builder 2007) currently accepts it without warning, but I've had comments that this is an error in C++.


Let $f\in L^1(-\infty, +\infty)$ and $g(t) = \int_{-\infty}^{+\infty}|f(x+t) - f(x)|dx$. How to show that $\lim_{t\to0}g(t) = 0$? Originally I thought that we need to use . However, it is not necessary that such $h(x)$ exists that $|f(x + t_n)| < h(x)$.  I have this question from reading the proof of approximating $f$ with a continuous function. So we cannot use this fact! Thank you.

I am having a hard time with the following real analysis qual problem.  Any help would be awesome.  Suppose that $f \in L^p(\mathbb{R})$, where $1\leq p< + \infty$. Let $T_r(f)(t)=f(t−r)$. Show that $\lim_{r \to 0} \|T_rf−f\|_{L_p} =0$, that is $$ \lim_{r\to 0} \left( \int_{\mathbb R} |f(t-r) - f(t)|^p \mathrm d t\right)^{1/p} =0.$$


My shop has 20-items with a recommender system on top which analyses history of purchases and recommends items to buy each time customer returns.   Now I want to add an additional item to choose from, which I have no history about previous purchases (let's say customers purchased it from my competitor). In a while, I will  add this new item to recommender engine, but I'm afraid it will think that the item is less popular than 20-items with good history.  I guess I need to add some kind of adjustment to recommender engine, and (as  I'm newbie to recommender system)  what kind of adjustments should I look at/google for? Should I look at cold-start problem, like was proposed ?

I'm working on movie recommendation algorithm. The data set consists of about 40 million ratings (user, film, rating). I want to separate the ratings into two groups - training set and probe set. The training set will be used for training, probe set for checking that the algorithm doesn't overfit the data.  My first plan was to try to follow this approach: . They create the probe set by taking the last 3 ratings from every user (and every user is guaranteed to have 20+ ratings). But the problem is, what if there is some really new film whose all ratings are in the probe set? The training algorithm wouldn't have any info about this film.


Bastille is missing from the Ubuntu 14.04 universe repository. The main question - what should I do to replace the security provided by Bastille?  There must be a reason it was removed so how do I make up for it securely?

I followed the .  I enabled universe repository. But apt-get and aptitude both fail with "no candidate found".  I assume this means Bastille is not available for Saucy?  Any assistance would be appreciated.


When do you use the Monopoly development card? Before or after rolling the dice? Please explain why using the official rules.

In Settlers of Catan, I have always played that you can play a knight development card before your turn, which is obviously useful to get the robber off or your own hex before you roll the dice. Is this the same with all playable development cards? I have played lots of Catan but I have never raised this question with my friends before since I did not think there was any scenario in which it would be advantageous to play a different Development card before rolling.   However, consider this scenario:  I have 11 cards (6 ore, 4 wheat, 1 brick), 8 victory points, and the ability to build 2 cities next turn, giving me the victory. If I roll a 7, I will lose 5 cards, which will ruin my ability to build both cities and win on my turn. If, however, I play a Monopoly and take 8 arbitrary resources (say lumber), even if a 7 is rolled I will lose 9 resources but still be able to keep the 10 resources (4 wheat, 6 ore) necessary to build my cities and win.   Does anyone know if in situations like this it legal to play any playable development card prior to rolling?  Also, I still cannot see a benefit to playing a Road Building card prior to rolling. Anyone have any ideas?  Thanks!


#!/usr/bin/python  import rospy import serial import time from std_msgs.msg import String  ser = serial.Serial('/dev/ttyUSB0', 9600) print (ser.name) time.sleep(2)  #=========================================================== # An o y ine i kateuthynsi kinisis (mikos deksamenis) # Gia kinisi se eutheia x_d = 0 # mm y_d = 2000 thita_d = 0 # moires i rads #===========================================================  camera = [0, 0, 0] error = [0, 0, 0] data = [0, 0, 0] print(data) def camera_feedback():     # dedomena apo camera-RPi-seiriaka apo allon komvo mallon...     #camera = [x_c, y_c, thita_c]     #x_c = camera[0]                    #isws mpei kwdikas gia na diavazei apo tin     camera[0] = 0     #y_c = camera[1]                    #seiriaki tu RPi (opws to serial_connection())     camera[1] = camera[1] + 250     #thita_c = camera[2]         camera[2] = 0     print(camera)  def error_calculation():     error[0] = x_d - camera[0]     error[1] = y_d - camera[1]     error[2] = thita_d - camera[2]     print(error)  def controller_equations():     # edw mpenun oi eksiswseis tu michali     # kapws pernei to error kai alla dedomena kai dinei w, A, thita_mesi gia na stalun ston PIC     if error != [0, 0, 0]:         print(error)         print(data)         data[0] = 8         data[1] = 8         data[2] = 0     else:         data = [0, 0, 0]     print('kokos')     #data = [w, A, thita_mesi]     #na dw ti format dexete o kwdikas tu PIC  def serial_connection():     rospy.init_node('serial_connection', anonymous = True)     rate = rospy.Rate(10) #isws na min xreiazetai      if not rospy.is_shutdown():          ##data1 = bytearray(data)         ##rdata = bytearray()         ##rdata.extend(data1[0:2])         ##rdata.extend(data1[2:5])         ##vect = list(rdata)         ##print(vect)          if ser.isOpen():             print ("Port Open")             for i in range(1):                 #ser.write(b'5')                 #ser.write(chr(5)) auto stelnei kwdikopoiimenus xaraktires, ox$                 #ser.write(5)                 ser.write(bytes(data) + '\n')                 #print ('Hola!')                 #ser.write("Hola!\n")                 time.sleep(1)                 rate.sleep()  if __name__ == '__main__':     try:         while not rospy.is_shutdown():             camera_feedback()             error_calculation()             controller_equations()             serial_connection()         ser.close()     except rospy.ROSInterruptException:         pass   I run the code above and I get the error: UnboundLocalError: local variable 'data' referenced before assignment  I want to change the value of the global variable data through the function controller_equations(). I did the same with the variable camera in the function camera_feedback() without any error. I searched other posts for an answer but all of them say that is not possible to chance a global variable through a function. Any possible solution or a tip will be appreciated.  I am new in Python and I use Ubuntu 16.04 and Python 2.7.   Thanks in advance.

How can I create or use a global variable in a function?  If I create a global variable in one function, how can I use that global variable in another function? Do I need to store the global variable in a local variable of the function which needs its access?


Nevertheless, the crucial factor in the fleet’s demise was the Japanese attacks which had forced the Mongol commanders to have their large and unwieldy ships lashed together using chains. It was this defensive measure which proved fatal, come the typhoon.      — Mark Cartwright, “The Mongol Invasions of Japan, 1274 & 1281 CE” (Article), , 02 July 2019.    This is the article that I've been reading but I do not understand the last sentence, especially the “come the typhoon” part.  What does this mean?

From NPR, transcript .     Michelle Scott is reading from the Common Core math standards for   fifth-graders. She'll be teaching fifth next year, along with John   Gries. And together, they're writing—and rewriting—lessons   they'll need come September.   For the last sentence, did he want to say, “they're re-writing lessons they'll need if September comes”? He inverted the last part, put the verb “come” in the front and omitted “if”, right?   As far as I could determine, it seems only “if” with subjunctive voice could be used in this way. I don't think it's a subjunctive voice. In my impression, the subjunctive voice stands for those occasions when you're not sure whether it will happen or not, such as “If it were to rain, I'd pick you up.”   September will come sooner or later (it's not in limbo), so I'm wondering how to explain the sentence.


I want multiple references to appear like [8-10] instead of [8]-[10]. I am using \usepackage{cite}. I tried \usepackage[sort&compress]{natbib} but box brackets [] are replaced with round brackets () which is also undesirable.

I'm using a  freely downloadable latex class file and the style is set to \bibliographystyle{ieeetr}. But when I cite something with \cite{} I get it inside ().   For example I get it as abc et al. (1) but what I want to get is abc et al. [1].   Please tell me how to get my citations inside [ ] ?


i am from Pakistan and wish to travel from lahore to jeddah via uae along with my wife and son.  can i get visa on arrival at the airport?  Also tell me the visa fees

We are about to visit the United States. Our travel itinerary on Etihad Airways is as follows:  Departure flight Colombo - Abu Dhabi 8.25 hr layover - Los Angeles   Return flight Chicago  - Abu Dhabi 15 hr layover - Colombo  Do we need transit visas for connections in the UAE?   Do we have to re-check our baggage in Abu Dhabi, as well? If we do, would we require a visa


Production server (This is the correct behaviour)  >>> $str = "àáâãäåæçèéêëìíîïðñòóôõöøùúûüý"; => "àáâãäåæçèéêëìíîïðñòóôõöøùúûüý" >>> strtoupper($str); => "àáâãäåæçèéêëìíîïðñòóôõöøùúûüý" >>> mb_strtoupper($str); => "ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖØÙÚÛÜÝ"   New local environment  >>> $str = "àáâãäåæçèéêëìíîïðñòóôõöøùúûüý"; => "àáâãäåæçèéêëìíîïðñòóôõöøùúûüý</string>" >>> strtoupper($str); => "ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖØÙÚÛÜÝ</string>" >>> mb_strtoupper($str); => "ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖØÙÚÛÜÝ</string>"   I can't find anything on the internet regarding this </string> at the end of the variable.  It also fails with iconv function   Production server  >>> iconv('UTF-8', 'ASCII//TRANSLIT', 'áè'); => "ae"   New local environment  >>> iconv('UTF-8', 'ASCII//TRANSLIT', 'áè'); => "'a`e"    I followed the instructions regarding PHP found in  but no luck, I ignored MySQL since I'm not using it, I also ignored the Apache one since I have Nginx.  I started to think it's because mbstring extension but can't find anything related with that.  EDIT: It's not a duplicate  because it's not an issue with MySQL and I already tried the solutions exposed there. It's not a matter of get an alternative for iconv but to fix the environment to do the same as Production.

I'm setting up a new server and want to support UTF-8 fully in my web application. I have tried this in the past on existing servers and always seem to end up having to fall back to ISO-8859-1.  Where exactly do I need to set the encoding/charsets? I'm aware that I need to configure Apache, MySQL, and PHP to do this — is there some standard checklist I can follow, or perhaps troubleshoot where the mismatches occur?  This is for a new Linux server, running MySQL 5, PHP, 5 and Apache 2.


An entire function is of finite order $\rho$ if $$\rho = \inf \{\lambda \geq 0  \ | \ \exists A, B > 0 \ s.t. \  |f(z)|\leq Ae^{B|z|^{\lambda}} \forall z \in \mathbb{C} \}$$  Write $M(r) = \sup_{|z|=r}|f(z)|$. Then we have $$\rho = \limsup_{r \rightarrow + \infty} \frac{\log \log M(r)}{\log r}$$  Any hint ?

Let $f: \mathbb C \to \mathbb C$ be an entire function. The order of $f$ is defined by $$\lambda=\limsup_{r \to \infty} \frac{\log \log M(r)}{\log r}, $$ where $$M(r)=\max_{|z|=r} |f(z)| .$$  Ahlfors in his Complex Analysis claims that     "According to this definition $\lambda$ is the smallest number such that       $$M(r)\leq e^{r^{\lambda+\varepsilon}} $$ for any given $\varepsilon > 0$ as soon as $r$ is sufficiently large."   Why is this true?  My attempt:  We know that $$\lambda=\lim_{\rho \to \infty} \sup_{r \geq \rho} \frac{\log \log M(r)}{\log r}. $$  From the definition of the limit we have that for any $\varepsilon>0$, there exists some $\rho_0>0$, such that $$\left\lvert \sup_{r \geq \rho} \frac{\log \log M(r)}{\log r}-\lambda \right\rvert \leq \varepsilon ,$$ for every $\rho \geq \rho_0$. In other words $$\frac{\log \log M(r)}{\log r} \leq \lambda+\varepsilon $$ for every $r \geq \rho_0$. From here it is easy to see that $$M(r)\leq e^{r^{\lambda+\varepsilon}}, $$ for all $r \geq \rho_0$. I cannot see why $\lambda$ is the smallest number with this property.  Thanks in advance.