I want to ask a question about programming languages that is opinion-based. , where it was quickly closed. I tried to find another StackExchange site, but cannot find one.  I understand that these questions do not belong in StackOverflow, but where to go to with them? Many opinion-based questions are interesting and many people can learn valuable things from other people's opinions and tips.
After my lie down, I posted  on SO. As I suspected would happen, it got moved to programmers. Unfortunately, the kind of people I'm interested in getting answers from (litb,skeet et al - the top SO programmers in their respective disciplines) don't frequent Programmers much. So my question is, where to ask somewhat non-specific questions of high-powered users?
How to calculate $\int \frac{x^2 }{(x^2+1)^2} dx$? I'm trying  to calculate $\int \frac{x^2 }{(x^2+1)^2} dx$ by using the formula: $$ \int udv = uv -\int vdu $$  I supposed that $u=x$ s.t $du=dx$, and also that $dv=\frac{x}{(x^2+1)^2}dx$, but I couldn't calculate the last integral. what is the tick here?           the answer must be: $ \frac{1}{2}arctan\ x - \frac{x}{2(1+x^2)} $ + C Definition of $\mathbb{R}^\infty$ Suppose Alice publishes a book with a public key in it, and later wants to prove that she wrote the book. She could sign challenge messages with her private key, and others could verify those signed messages. Alice is proving she knows a private key without revealing anything about it.  Is this an example of an interactive zero knowledge proof?   Or does this example somehow not apply to zero knowledge proofs? How to completely remove Notepad++ in Ubuntu 18.04 terminal?  I can't find it in Synaptic package manager, and don't know where is on system, but I can see an icon in Activity. It is probably not completely installed, because I can't open it. Can an iOS user play with pc users? I have a Mac only, so I am not able to get Terraria through Steam. I was wondering if I can play Terraria on my iPad Mini with a friend who has it on his PC. I was wondering this, because I saw that Deepworld on iOS is compatible with the Mac version. One Object won't Show up in Final Render even though it shows up in the Preview Render Significance of starting the Fibonacci sequence with 0, 1.... DISCLAIMER: I do not deal with in-depth mathematics on a daily basis as some of you may, so please pardon my ignorance or lack of coherence on this topic.  QUESTION: What is the significance of starting the Fibonacci sequence with $0,1$ ?  For instance, if I picked any two random integers, say 2 and 7, to start a sequence would I actually be creating some multiple or derivation of the Fibonacci sequence?  Is there a general mathematical explanation for the relationship between any sequence represented by $a[0] = x, a[1] = y, a[n] = a[n-1] + a[n-2]$ and the Fibonacci sequence?  Or, back to my example sequence, is there a general mathematical relationship between:  $2,7,9,16,25,41,66,107,173,280...$  and  $0,1,1,2,3,5,8,13,21,34...$  Perhaps the Golden Ratio explains it somehow?  Any help would be appreciated. I'm unable to uninstall MATLAB;  sandeep@sandeep-VPCEH28FN:~$ sudo rm /var/tmp/lm_TMW* [sudo] password for sandeep:  rm: cannot remove '/var/tmp/lm_TMW*': No such file or directory sandeep@sandeep-VPCEH28FN:~$ sudo apt-get purge matlab 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? sandeep@sandeep-VPCEH28FN:~$ sudo apt-get purge matlab-support 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? sandeep@sandeep-VPCEH28FN:~$ Why would Louise telling the Chinese commander about his wife's last words change his mind? In the future in Arrival, the commander says that he changed his mind about going to war with the aliens because Louise called his private number and told him his wife's dying words. My question is what did Louise say to him (like in English) and why did it change his mind? Attaching towel rail to drywall It is a theorem in elementary number theory that if $p$ is a prime and congruent to 1 mod 4, then it is the sum of two squares. Apparently there is a trick involving arithmetic in the gaussian integers that lets you prove this quickly. Can anyone explain it? How to enforce sender address to be "logged-in-user@example.org" in Postfix? I have set up a Postfix server with SMTP AUTH (STARTTLS on port 587). All my users are in the domain "example.org". I want to enforce the sender address to be "logged-in-user@example.org".  I learned that this can be achieved with the main.cf options  smtpd_sender_restrictions = reject_sender_login_mismatch, ... smtpd_sender_login_maps = hash:/etc/postfix/smtpd_sender_login_maps   with a login_maps file like:  a@example.org a b@example.org b c@example.org c ...   (see also ), but this would mean I'll have to edit the login_maps file every time I have a new user. I don't need such a flexible mapping: It should always be "logged-in-user@example.org". Is there an easier option? Configuring ADB for Nexus 4 on Ubuntu 11.10 I'm trying to deploy and test an Android app on my Nexus 4 from my Ubuntu 11.10 computer, but ADB doesn't recognize it. I think I need the Google USB drivers, but I cannot find instructions on how to install them on Ubuntu.  How can I install the drivers on Ubuntu 11.10 so that ADB will recognize my N4? Setting the correct encoding when piping stdout in Python When piping the output of a Python program, the Python interpreter gets confused about encoding and sets it to None. This means a program like this:  # -*- coding: utf-8 -*- print u"åäö"   will work fine when run normally, but fail with:     UnicodeEncodeError: 'ascii' codec can't encode character u'\xa0' in position 0: ordinal not in range(128)   when used in a pipe sequence.  What is the best way to make this work when piping? Can I just tell it to use whatever encoding the shell/filesystem/whatever is using?   The suggestions I have seen thus far is to modify your site.py directly, or hardcoding the defaultencoding using this hack:  # -*- coding: utf-8 -*- import sys reload(sys) sys.setdefaultencoding('utf-8') print u"åäö"   Is there a better way to make piping work? How do I get console output in C++ with a Windows program? Object has no method 'live' - jQuery Can prematurely powering down a computer cause bad sectors in a hard drive? Does "Going Infinite" necessarily end the game? For $G$ a group and $H\unlhd G$, then $G$ is solvable iff $H$ and $G/H$ are solvable? I recently read the well known theorem that for a group $G$ and $H$ a normal subgroup of $G$, then $G$ is solvable if and only if $H$ and $G/H$ are solvable. In my book, only the fact that $G$ is solvable implies $H$ is solvable was proven. I was able to show that if $H$ and $G/H$ are solvable, then so is $G$, but I can't quite show that $G$ is solvable implies $G/H$ is solvable.   My idea was this. Since $G$ is solvable, there exists a normal abelian tower $$ G=G_0\supset G_1\supset\cdots\supset G_r=\{e\}. $$ I let $K_i=G_i/(H\cap G_i)$, in hopes of getting a sequence $$ G/H\supset K_1\supset\cdots\supset K_r=\{e\}. $$ My hunch is that the above is also a normal abelian tower. However, I'm having trouble verifying that $K_{i+1}\unlhd K_i$ and that $K_i/K_{i+1}$ is abelian.  Writing $H_i=H\cap G_i$, I take $gH_{i+1}\in K_{i+1}$ for some $g\in G_{i+1}$. If $g&#39;H_i\in K_i$, then I want to show $g&#39;H_igH_{i+1}g&#39;^{-1}H_i$ is still in $K_{i+1}$, but manipulating the cosets threw me off. I also tried to use either the second or third isomorphism theorems to show that $K_i/K_{i+1}$ is abelian, but I'm not clear on how to apply it exactly. I'd be grateful to see how this result comes through. Thank you. What is the weight equation through general relativity?