Ok, this is a completely unknown area for me but it struck my curiosity so I did some digging. Take it for what it's worth.
MathML is a markup language that is supported by W3.org which can be added to HTML in order to display complex formulas:
It appears there are several libraries to convert LaTex to MathML. The problem with MathML is that Chrome doesn't support it.
However, MathJax appears to be able to convert LaTex into something that displays on all browsers using CSS and webfonts which C3 does handle.
And, it's JS which you should be able to either link to or include in a C3 project.
So, now that you have it as HTML, what do do with it?
I've been using this plugin to do Ajax calls to a server, grab html and display them in a C3 project. While I have found some minor issues with it, it seems to mostly work. Once you learn it, the HTMLElement also has some other interesting features that might work really well with formulas. First of all, since the HTML is loaded into the plugin, you can parse it and edit it and it instantly changes. You could have a text field, paste in your LaTex, let MathJax convert it and then place it in the HTMLElement to display it. That plugin also has the ability to make clickable elements in the HTML that can be used to call a C3 function.
Because MathJax uses CSS you can use another plugin from the same author to solve that problem:
I've been using that to successfully load both JS and CSS from a webserver into my C3 project. And the loaded CSS works with the above plugin to display the HTML however you wish.
With a little creativity, I believe that you could duplicate this website in a C3 project:
Therefore, including it in C3, IMHO, would cause unneeded bloat and would divert Scirra's limited resources onto a project that only a handful of end users would need. If the ideas I presented above could be made to work, that would be ideal.