I suggest using a link to Meta Math SE. It contains a lot of examples, allows to invoke editing (to grab the relevant MathJax template). This is also the page that is right now used at Physics SE. I currently do not see, why we would want to create our own Meta post for that, as we don't have anything custom (as opposed to Chemistry SE).
Thanks to Shog, this is now done.
We also noticed that you didn't have MathJax activated on Meta, so we've turned that on and updated the link in the meta help page to also link to the Mathematics guide to MathJax.