The following steemit post:

https://steemit.com/steemit/@cryptovest/missing-markdown-functionalities-on-steemit-footnotes-and-mathjax-latex

also discusses this issue. Looks like there was a feature request for mathjax in steemit:

https://github.com/steemit/condenser/issues/7

I wonder how stackexchange dealt with the security issues that led this feature request to be closed?

I wonder how hard it would be to fork the UI:

https://github.com/steemit/condenser

and try implementing this?