# Where can I find the explanation for the LaTeX/mathjax symbology used for equations in physics.stackexchange.com?

I'm trying to understand the answers given to the question: How long it will take for a tree to fall on a ground?

For example how are the following to be interpreted $\ { } and what are: frac mgh mh mathcal partial left right I seem unable to find any sort of "introduction" to physics.stackexchange. I'd appreciate being pointed in the right direction. I tried to ask this question on "meta" as directed - but found I need "five reputation" - & can find nothing telling what this is and how to earn them. Also please advise of all the faux pas made herein - ## migrated from physics.stackexchange.comMar 4 '11 at 3:13 This question came from our site for active researchers, academics and students of physics. I've flagged your question for moderator attention as it should be on meta. They'll be along sooner or later to migrate it there (and perhaps fix up the tags). – dmckee Mar 4 '11 at 2:56 – Qmechanic Oct 12 '12 at 12:11 codecogs.com/latex/eqneditor.php is a good a Latex input method. – Alyosha Feb 3 '13 at 16:47 ## 3 Answers If you actually see $ signs instead of nicely rendered equations this means either that you have javascript disabled or that the post you're looking at contains errors. In the latter case flag for moderator attention so it gets fixed. For a test, look at this answer which contains a squareroot. If instead you see \$\sqrt etc. you need to enable JavaScript.

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It is essentially LaTeX. See http://www.math.harvard.edu/texman/. The JavaScript tool that handles the translation is called MathJax.

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I had the same question, and found this site, with its examples, of value: http://www.andy-roberts.net/misc/latex/latextutorial9.html

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