MathJax ($\LaTeX$ in posts) is live!

We have MathJax

In this meta we discussed, requested, and gathered evidence for the utility of MathJax in RPG.SE posts.

Now it's time to use MathJax

For those familiar with LaTeX it will likely suffice to say that $...$ are our delimiters ($$...$$ for equations centered on their own line), and to let you experiment. Then there's this MathJax reference for your reference, and Math.SE has made a MathJax basic tutorial and quick reference.