This is a two part question:
The extent to which tex can be incorporated into a post appears to be outlined here (some links from that question need refreshing btw). Is this the main source of information on tex incorporation/rendering in general or should I consult another post?
This question would have gained from inclusion of the "d-slashed" symbol. I found tex representations of this symbol in package tipa (as \textcrd). Any other way this symbol could be included?
I realize this is probably a dupe of sorts. Links to "authoritative" posts are very welcome since I was unable to find an answer.
I have also also looked through the sandboxes, so far no luck, despite the impressive array of nifty symbols on display. Ironically orthocresol apologizes there about not using proper notation for the inexact differential :-).
Note that the d-slash symbol is the last in the list in Martin's answer. I understand that tex and mathjax are not the same thing, but having seen various tex items implemented I thought this was one way to go. I have also seen here implementation of the Angstrom symbol using \AA via \require.