How to prove $f(x_1,\ldots,x_n) = \sum x_i\ln x_i - (\sum x_i )\ln(\sum x_i)$ is convex on R++
convexity proof of a function including ln and sums
Get variable from PHP to JavaScript I want to use a PHP variable in JavaScript. How is it possible? mkdir error: no such file or directory on a linux machine running CENTOS v 7.8.2003 I am in a directory Neutrinos I now do  mkdir /pionloop/ this works. I then go to into this new directory pionloop and do mkdir /E_0.3 and this works as well. I thus have as a result a directory Neutrinos/pionloop/E_0.3.  Now, starting in Neutrinos I want to do this in one command and therefore do mkdir /pionloop/E_0.3 and get: `mkdir: cannot create directory ‘/pionloop/E_3.0’: No such file or directory  What is going wrong here?? How to execute two mysql queries as one in PHP/MYSQL? How can magnets be used to pick up pieces of metal when the force from a magnetic field does no work? I learned that the force from a magnetic field does no work. However I was wondering how magnets can be used to pick up pieces of metal like small paperclips and stuff. I also was wondering how magnets can stick to pieces of metal like a refrigerator? I want to play a game in an older update, but can't see a way to choose a specific version. Is this possible? Applying PCA to data that fail a normality test Unable to change privacy settings upon install of Ubuntu 18.04 LTS Remmina remoteapp over RDP I was wondering how to use remmina to open applications on a Windows machine over rdp using remoteapp (or seamless or whatever it's actually called).  I've already used Kim Knight's  to set up remoteapp on a Windows 7 machine and I can connect and run remote apps fine from another windows box.  Allegedly FreeRDP (which Remmina uses for its RDP Plugin) has support for remoteapp. I'm not sure how to make use of it though. I can't find any examples of people actually doing this online but there is a , from which I can infer that there is some way to run remote apps.   I've tried many combinations of settings for Client, Startup Program and Startup Path in the Advanced tab when configuring an RDP connection in Remmina, but I can't make it work. I can connect to Windows boxes with RDP just fine, just not running a remoteapp. Train loss and accuracy In theory, is it possible that the loss on the train set will increase together with the train set accuracy? (in the normal case the train set loss should go down) And vice versa, can the train loss decrease along with the accuracy?   Note: This is obviously different than the classic underfit / overfit cases which are easier to grasp. Getting HTTP/2 Working on Apache 2.4.29 on Debian 8 I am trying to update my apache2 (Apache/2.4.29 (Debian 8)) server to support http2 but after enabling http2   with following code, it does not work because of mpm_prefork does not support http2  &lt;IfModule http2_module&gt;     ProtocolsHonorOrder On     Protocols h2 h2c http/1.1 &lt;/IfModule&gt;    since mpm_prefork apache (2.4.29)  does not work with http2, I tried using  mpm_event/mpm_worker but it does not work, so I enable mpm_prefork  sudo a2dismod mpm_event  sudo a2dismod mpm_worker  sudo a2enmod mpm_prefork   Since I am still running php5 what should I do to have http2 support on Debian8?  Will I have to update php5 to php7?  Is there any workaround to use mpm_worker/mpm_event with php5 with http2 support?  apache error log  [http2:warn] [pid 11992] AH10034: The mpm module (prefork.c) is not supported by mod_http2. The mpm determines how things are processed in your server. HTTP/2 has more demands in this regard and the currently selected mpm will just not do. This is an advisory warning. Your server will continue to work, but the HTTP/2 protocol will be inactive. [mpm_prefork:notice] [pid 11992] AH00163: Apache/2.4.29 (Debian) OpenSSL/1.1.0g configured -- resuming normal operations [core:notice] [pid 11992] AH00094: Command line: '/usr/sbin/apache2' When I use the \tableofcontents macro in a document where the etoc package is loaded, latex pauses and reports an error. If I let the compilation continue a well formed pdf is generated.  Minimal example that can reproduce the error on my machine.  \listfiles \documentclass{article} \usepackage{etoc}  \begin{document} \tableofcontents‎‎ \end{document}   Output from pdflatex on the minimal example.  This is pdfTeX, Version 3.14159265-2.6-1.40.19 (TeX Live 2018) (preloaded format=pdflatex)  restricted \write18 enabled. entering extended mode (./mwe.tex LaTeX2e &lt;2018-04-01&gt; patch level 4 (/usr/local/texlive/2018/texmf-dist/tex/latex/base/article.cls Document Class: article 2014/09/29 v1.4h Standard LaTeX document class (/usr/local/texlive/2018/texmf-dist/tex/latex/base/size10.clo)) (/usr/local/texlive/2018/texmf-dist/tex/latex/etoc/etoc.sty (/usr/local/texlive/2018/texmf-dist/tex/latex/tools/multicol.sty)) (./mwe.aux)  ! Package inputenc Error: Unicode character ‎ (U+200E) (inputenc)                not set up for use with LaTeX.  See the inputenc package documentation for explanation. Type  H &lt;return&gt;  for immediate help.  ...                                                l.6 \tableofcontents‎                        ‎ ? R OK, entering \nonstopmode...  ! Package inputenc Error: Unicode character ‎ (U+200E) (inputenc)                not set up for use with LaTeX.  See the inputenc package documentation for explanation. Type  H &lt;return&gt;  for immediate help.  ...                                                l.6 \tableofcontents‎‎  [1{/usr/local/texlive/2018/texmf-var/fonts/map/pdftex/updmap/pdftex.map}] (./mwe.aux)   *File List*  article.cls    2014/09/29 v1.4h Standard LaTeX document class   size10.clo    2014/09/29 v1.4h Standard LaTeX file (size option)     etoc.sty    2018/02/23 v1.08n Completely customisable TOCs (JFB) multicol.sty    2018/04/20 v1.8s multicolumn formatting (FMi)  ***********   ) (see the transcript file for additional information)&lt;/usr/local/texlive/2018/te xmf-dist/fonts/type1/public/amsfonts/cm/cmbx12.pfb&gt;&lt;/usr/local/texlive/2018/tex mf-dist/fonts/type1/public/amsfonts/cm/cmr10.pfb&gt; Output written on mwe.pdf (1 page, 16281 bytes). SyncTeX written on mwe.synctex.gz. Transcript written on mwe.log. Reputation displaying incorrectly on Careers (for some accounts) When I go to , go to the "Stack Exchange" section, and click on "edit" under "Accounts", I see the following at the bottom of the account list (partially truncated for reasons of space):    Now, as you can see from my reputation here on MSO, I should have the association bonus on all sites where I have an account. Yet, for some reason, my accounts on Android, Italian, Sound Design, and Windows Phone are listed as having just 1 reputation. However, if you look at my account on each of these sites (, , , and ), you will see that I do, indeed, have 101 reputation from the association bonus.   At first, I thought the commonality among those four sites was that I hadn't performed any actions on them (not even voting), but it turns out that I have actually cast a vote on Android, so I don't really know what's up.   Note also that all of these accounts are at least a few weeks old (and my association bonus is even older than that), so this doesn't seem like it would be a caching issue or anything. How to find the last field using 'cut' Short Story about interminable rain on Venus Can I insert elements to the beginning of an element using .appendChild()? If the user selects an option in a dropdown box, there must be added a label and a textbox. Using appendChild, these elements get added to the end of the container.  var newFreeformLabel = document.createElement('label'); newFreeformLabel.innerHTML = 'Omschrijving:';  var newFreeformField = document.createElement('input'); newFreeformField.className = 'textfield'; newFreeformField.name = 'factuur_orderregel[]';  var newFreeformSpacer = document.createElement('div'); newFreeformSpacer.className = 'spacer';  container.appendChild(newFreeformLabel); container.appendChild(newFreeformField); container.appendChild(newFreeformSpacer);   The issue is that these elements should be inserted at the beginning of container, not at the end.  Is there a solution to this in PrototypeJS? How to select more layers with GIMP? In Adobe Photoshop I am able to select multiple layers at once with Shift+Click.  How can I do that in GIMP? I'm taking a complex analysis course and doing some practice computing residues &amp; evaluating integrals. I pulled out an old book called     On page 196-197, there are some interesting integrals to evaluate. I'm at 5.4.3.10.: I was able to do question 1, but was stumped at how to even begin with question 2:     Evaluate the integral   $$\int_0^{2 \pi} e^{\cos x} \cos (nx - \sin x) \,dx ,$$   where $n$ is an natural number.   The answer is simply $\frac{2 \pi}{n}$. Any hints? How to enable automatic update in wordpress running on IIS7 and Windows 2008? I have a dedicated server using Windows 2008 and IIS7 running 5 blogs with Wordpress. I can't use the autoupdate feature of the wordpress neither the automatic plugin instalation.  I believe I must set writing permissions in some temporary folder, the question is which one. Do you have any idea? Accessing the index in 'for' loops? How do I access the index in a for loop like the following?  ints = [8, 23, 45, 12, 78] for i in ints:     print('item #{} = {}'.format(???, i))   I want to get this output:  item #1 = 8 item #2 = 23 item #3 = 45 item #4 = 12 item #5 = 78   When I loop through it using a for loop, how do I access the loop index, from 1 to 5 in this case? A generic list of anonymous class In C# 3.0 you can create anonymous class with the following syntax  var o = new { Id = 1, Name = "Foo" };   Is there a way to add these anonymous class to a generic list?  Example:  var o = new { Id = 1, Name = "Foo" }; var o1 = new { Id = 2, Name = "Bar" };  List&lt;var&gt; list = new List&lt;var&gt;(); list.Add(o); list.Add(o1);   Another Example:  List&lt;var&gt; list = new List&lt;var&gt;();  while (....) {     ....     list.Add(new {Id = x, Name = y});     .... }