After a recent update to our forum software, typesetting equations on SFN has changed a little bit. Although we are still using LaTeX, for a variety of reasons, we've elected to shift over from our custom-written LaTeX generator to the excellent MathJax library, which will take your equations from post text and render them in your browser.
Much as before, the idea is that in your post, you surround equations with special characters, and MathJax will convert the contained text into an equati

You need [math] tags around the Latex. (Note that there is also a bug in the forum SW that means it won't be rendered until you refresh the page)