November 11, 2014
April 9, 2017 - Update: The recent update of Pages makes all this work unnecessary. Apple has built into Pages the ability to interpret LaTeX and MathML. Not only is it easy to add equations to your documents from right within Pages, but you can (finally!) edit them by double-clicking the equation. Just put your cursor at the insertion point, press command+option+e and type the TeX or MathML code. You'll need at least Pages v6.1 to use this welcome addition.
I teach Math and Physics so I frequently need to typeset equations. I'm reasonably proficient in using LaTeX for typesetting equations, but I haven't spent enough time with it to learn how to TeX an entire document and make it look exactly as I would like. Until I do, my solution is to use Apple's Pages app (v5.6) for basic editting and the LaTeXiT "detect and typeset equations" service for typesetting formulas.
If you intend to proceed then you have some downloading to do. Note: if you are at my school all you need to do is install TeX in Self Service--I've done all the configuration for you. If you are not at my school then head over to the Mac TeX Users Group and download a TeX distribution. The full MacTeX-Live 2015 distribution is 2.4GB. If the size is a problem you can install just the MacTeX Basic and a front end package that contains GhostScript and a few GUI front ends for a total of around 300MB. LaTeXiT is included in the full MacTeX-Live and in the additional packages download or you can download it from the author. Install the TeX first and then LaTeXiT. Pierre is an "unknown developer" (i.e., he doesn't have a Developer ID from Apple so he can digitally sign his software) so depending on your OS version and GateKeeper settings you may need to secondary-click the app and select open to start LaTeXiT. After you open the app one time you won't need to open it before typesetting equations.
After everything is installed you're ready to begin typesetting equations in Pages (or Mail, TextEdit, etc.). Open Pages and write your article, report, test, etc. Where you need an equation delimit it with $$ for display mode or $ for inline. When you finish, highlight your text and click Pages/Services/detect and typeset equations. After a few seconds the equation will be typeset and nicely aligned with the rest of your text. Here's an example:
If you have too many equations (I don't know how many is too many) in the text you select, it will fail without reporting an error. Just select less text and try again. If the "detect and typeset equations" service is not available you can configure that in Latexit/preferences/service/keyboard shortcuts--you can even set a hot key if you want. If you are new to TeX there is a lot of help on the web. The American Mathematical Society Short Math Guide is a great place to start.