You can use LaTeX notation to typeset mathematics within a post and within titles.
For example, if f(x) = e^{-x^2}, then
\int_{-\infty}^{\infty} e^{-x^2} \, dx = \sqrt{\pi}.
I typed that into the editor like so:
For example, if $f(x) = e^{-x^2}$, then
$$\int_{-\infty}^{\infty} e^{-x^2} \, dx = \sqrt{\pi}.$$