# The "$$" math display syntax is broken by the "\" escape sequence Pretty simple bug. If you try to type a full displaymath equation on another site, you would normally start it with $$.

This doesn't work this site, because the site interprets it as \. Thus, the opening dollar sign is rendered into the equation, and the closing dollar sign is left off. It's also not displayed as full-size math. This is how it renders:

\$$\mbox{math}\$$

\$\mbox{math}\$


renders as

\$\mbox{math}\$

$$\mbox{math}$$


renders as

$$\mbox{math}$$

In Chrome, they both look correct to me. Are you sure it isn't just a typo?

• Ah, this makes sense. An escape character was added to P.SE's MathJax, and I assumed it applied to  as well. My apologies!
– user20
May 23 '14 at 6:33
• @Emrakul I made the same mistake at first, trying to use \$\$ as an escape sequence. But that's actually an empty regular MathJax snippet, so I ended up with a post with bare MathJax codes, which due to MathJax's forgiveness, got half-rendered. Very confusing.
– SQB
May 23 '14 at 6:38