hmm...if we can get embedded images to work, we're set.

http://www.codecogs.com/png.latex?\int_a^b\frac{1}{\sqrt{x}}dx

Click that link, and you'll get a rendered png of the LaTeX expression I've placed after the ?. Replace that expression with another and, well, you'll get that too. If you're writing a top-level post, you can use this to pretty quickly embed equations. Not sure how to make it useful in a comment though.