There are other sandboxes available across the Stack Exchange network however each site can be a little different than other sites, for instance we have MathJax enabled here while some other sites don't. There are tools enabled on other sites that aren't enabled here.

This will help those that aren't interested in traveling to other sites and searching for their sandboxes, as well as those needing to know exactly what works on this site and what doesn't.

For some reason the mathjax blocks aren't working in preview on the main site.

$$5=\sqrt{25}$$

Inline math is ok, though: $5=\sqrt{25}$

Here's an example directly from the math.stackexchange.com markdown help:

The Gamma function satisfying $\Gamma(n) = (n-1)!\quad\forall n\in\mathbb N$ is via through the Euler integral

$$\Gamma(z) = \int_0^\infty t^{z-1}e^{-t}dt\,.$$

This works, though. Guess I need to understand what's wrong with my latex math in the other answer, then... Looks like blank lines are a problem. But then if you have a series of equations, they all appear on one line:

$$V = IR I = \frac{V}{R} P = VI P = I^2R I = \sqrt{\frac{P}{R}}$$

So the answer is that each individual equation has to be delimited?

$$V = IR$$ $$I = \frac{V}{R}$$ $$P = VI$$ $$P = I^2R$$ $$I = \sqrt{\frac{P}{R}}$$

Somewhat defeats the purpose of the block, it seems. Guess I need to find out what latex requires for a new line.

$$V = IR\\ I = \frac{V}{R}\\ P = VI\\ P = I^2R\\ I = \sqrt{\frac{P}{R}}$$

And the answer is that each line may be split with two backslashes: \\

• If you want empty lines inside a mathjax block, you need to end them with a backslash. (I guess they aren't empty then). Jan 29, 2014 at 20:27