User blog:Peter Sway/Latex

I have tried a number of sources to understand how to enter equations using LaTex into a wiki.

They all seem to assume that it is easy but none of the examples provided work. There is no indication that one needs to change the environment to include a LaTeX processor -- no context data at all, as if all that is necessary is to preceed the LaTeX with

$$

L_1 =\text{ }\frac{1}{2} e_2\times  e_3 $$