How do I update the macro for partial derivative in order to accept standard second or bigger order?  I have so far \newcommand{\pderiv}[2]{\frac{\partial #1}{\partial #2}} for the first order derivative. I tried to make second order as a different command (\newcommand{\pderiv2}[2]{\frac{\partial^2 #1}{\partial {#2}^2}}) but I get an error because the argument #2 does not accept sub or superscripts. How to solve this?  I know I could use \pderiv{^2 Y}{X^2} to get the proper output but I want to make it easier. (MWE bellow)  \documentclass{article} \newcommand{\pderiv}[2]{\frac{\partial #1}{\partial #2}} %\newcommand{\pderiv2}[2]{\frac{\partial^2 #1}{\partial {#2}^2}}  \begin{document} $\pderiv{^2 Y}{X^2}$ is ok!!  \verb|\pderiv2| doesn't work  :( \end{document}
I was thinking about writing a partial derivative macro that has a similar syntax to the . ()  The syntax could be like this:   \D{f}{x} expands to \frac{\partial f}{\partial x} \D{f}{x,y} expands to \frac{\partial^2 f}{\partial x\,\partial y} \D{f}{{x,2},y} expands to  \frac{\partial^3 f}{\partial x^2\,\partial y} et cetera for any number of derivatives.   Bonus points for an optional argument so that for instance   \D[subscript]{f}{{x,2},y} expands to f_{xxy}   I looked at the  package but the syntax is a little tedious.  For instance, to get \frac{\partial^3 f}{\partial x^2\,\partial y} with that package I would need to do \md{f}{3}{x}{2}{y}{}.  And it doesn't generalize to three variables.  Before I dive in I thought I'd ask the hive and see what's been done.
Push Faces Like Sketchup Is there a way in Blender to push faces like Sketchup does?     The best I can get is doing a regular extrude and a lot of work to clean the "mess" up...    Thank you for your time! Puzzling Enumerable.Cast InvalidCastException The following throws an InvalidCastException.  IEnumerable&lt;int&gt; list = new List&lt;int&gt;() { 1 }; IEnumerable&lt;long&gt; castedList = list.Cast&lt;long&gt;(); Console.WriteLine(castedList.First());   Why?  I'm using Visual Studio 2008 SP1. What is the best way to vertically center the content of a div when the height of the content is variable.  In my particular case, the height of the container div is fixed, but it would be great if there were a solution that would work in cases where the container has a variable height as well. Also, I would love a solution with no, or very little use of CSS hacks and/or non-semantic markup. The latex file coding is not there but the pdf file is there I wrote all my coding in the .tex file. The next day when I opened it the coding is all gone and the pdf file is opening with it and is displayed as an output. How do I bring back my coding? crm 2011 how to hide/show the ribbon button with javascript How to pass parameters in batch file and zip the file using 7z.exe? I need to create a batch file as per below requirements  1) pass path1 &amp; path2 while running the batch file  exl: testrun.bat E:\ERP\test1.txt E:\ERP\header.txt  2) Need to store these command line paths values in batch file  exl: var1=E:\ERP\test1.txt var2=E:\ERP\header.txt  3) zip the path1 using PKZIPW.exe or 7z.exe and create new o/p zip file  exl: 7z.exe u -tzip E:\Erp\Test1.zip var1  4) copy path2 in newly created o/p file  exl: copy /b var2+test1.zip E:\Erp\Final_output.zip I recently changed my username to Undo. I was amazed when I pressed Submit and saw that it actually went through - surely someone somewhere was using this same username.  Out of curiosity, I then search the SO user list for Undo - and found  with Undo as thier name. They have 50 rep. I have around 1,500.   Is there some kind of pecking order, I.e. a high-rep user can 'steal' a low-rep user's name? Or is this a bug?  Or can two users have the same username without causing the SO servers to go down in a burning ring of fire? Is Iron Man stronger than the Hulk? In Avengers: Endgame, when Hulk initially uses the new Infinity Gauntlet, it takes a tremendous effort from him (in addition to almost burning his entire arm), in order to snap his fingers and restore the world as we knew it. Yet at the end of the movie, when Iron Man uses the Gauntlet, it seems very easy for him to snap his fingers.  How was Tony able to wield the stones with such ease when Hulk was clearly struggling with it? I just visited Ask Ubuntu (askubuntu.com) while logged into Stack Exchange, and noticed that "join this community" doesn't appear:    It is similarly broken on Math Overflow (mathoverflow.net). It works, however, on all sites that are subdomains of stackexchange.com, like Mathematics (math.stackexchange.com) and Academia.  I'm using Google Chrome version 46.0.2490.86 on Windows 8.1 Update 1.  (I don't know if this can actually be fixed, given how cookie security works, but I figured Stack Exchange should be aware of the issue.) Cannot see OpenLayers under Plugin in QGIS? Although I have installed the OpenLayers plugin in QGIS 2.4, I cannot see it in the list when I click on Plugins.    Does anyone else have this issue? Schrödinger Equation for Two Electrons? I'm having trouble finding a simple answer to this question (maybe because there isn't one), but I'm just confused about how the Schrödinger Equation would look for two electrons. I understand that it would exist in 6 dimensional configuration space, but how does the potential look? It's confusing that the potential would be different for each electron depending on where the other one is. How to custom (split in two)? Ibidem Derivative of inverse function at a point. Let $f\left(x\right)=x^{13}+3x^{9}+2x^{5}+x^{2}+x+2$ find $\left(f^{-1}\right)'\left(1\right)$. Can somebody show me the method? I am a little confused. How to pack the game files into one without using any file compressor? Well, one example is this file of the game The Sims 2 for PS2: quickdat.arc. The file contains this .arc extension, but it's no one an archive file and it contains some data of the game inside. How can I do this? Put so many files in one?  How to do something like this? All the game files inside one without using a file compressor? I am looking for a short story I read long ago about the phone system 'waking up'. It talks about how the phone system had just reached the number of connections as the number in the human brain. They lead you somehow to wonder (maybe characters speculating?) and it ends with a 'baby cry' of all the phones in the world ringing. I think I read it at least 20 years ago, maybe as many as 30. I think it was after 1978 because I think it was after I went to work at Bell Labs - so the phone connection resonated:-). It was definitely pre-internet.   What was the title? Who was the author? Any more on the plot since my memory is very hazy? I remember really liking the story and this site has got me thinking about my ATF's. What cross-platform command-line tool allows me to get my external IP address? How do I get my external IP address  from the Windows and Linux command line? On Windows, ipconfig shows an internal network IP address, but it does not show the external one. Possible Duplicate:          The FAQ specifies that:     Use your downvotes whenever you encounter an egregiously sloppy, no-effort-expended post, or an answer that is clearly and perhaps dangerously incorrect.   But if I find a correct question, closed (or not yet) as duplicate, is downvote a correct behavior for Stack&nbsp;Overflow policy? Changing subject and verb positions in statements and questions I need a number of different full-page DOM samples for my qUnit test suite Is there a proof that the ratio of a circle's diameter and the circumference is the same for all circles, that doesn't involve some kind of limiting process, e.g. a direct geometrical proof?