Wikidot.com uses MathJax to render beautiful LaTeX equations. For those that know LaTeX syntax using wikidot equations should be straightforward.
Simply put the equation between [[math label]] … [[/math]] block tags (the label is optional). The equation is rendered within LaTex \begin{equation} ... \end{equation} environment. Please refer to any LaTeX reference manual for details about syntax.
[[math label1]]
\rho _{\rm GJ} = -\sigma (r) \left[ (1 - \eta _{\ast }^2 {\kappa \over {\eta ^3}}) \cos \chi \right.
+ \left. {3\over 2} \theta (\eta) H(\eta)
\xi \sin \chi \cos \phi \right]
[[/math]]
To refer to a labeled equation simply use [[eref label]] to get a raw number or e.g. Eq. ([[eref label1]]) which gives Eq. (1).
You can specify the LaTeX environment in 2 ways, either by passing a type="<environment>" parameter, or using \begin{<environment>} and @\end{<environment>}@@ within the equation. E.q. these two are equivalent:
[[math type="align"]]
E = mc^2
[[/math]]
[[math]]
\begin{align}
E = mc^2
\end{align}
[[/math]]
The equation environment is default. Other supported math environments are: align, alignat, aligned, alignedat, array, Bmatrix, bmatrix, cases, eqnarray, equation, gather, gathered, matrix, multline, pmatrix, smallmatrix, split, subarray, Vmatrix, vmatrix.
To use math expressions inside text (sentence) use [[$ ... $]] block tags.
[[$ E = mc^2 $]] is much more popular than
[[$ G_{\mu\nu} - \Lambda g_{\mu\nu} = \kappa T_{\mu\nu} $]]
$E = mc^2$ is much more popular than $G_{\mu\nu} - \Lambda g_{\mu\nu} = \kappa T_{\mu\nu}$