Below is a JavaScriptMath example. It uses the javascript plugin, MathJax. The configuration is based the configuration used at stats.stackexchange.com and can additionally be configured to the suit the users needs.

Within-class ($S_W$) and between-class ($S_B$) scatter matrices are defined as:

$$ S_W = \sum_{i=1}^C\sum_{t=1}^N(x_t^i - \mu_i)(x_t^i - \mu_i)^T $$

$$ S_B = \sum_{i=1}^CN(\mu_i-\mu)(\mu_i-\mu)^T $$

Total scatter matrix $S_T$ is given as:

-- EricTorstenson - 08 Feb 2013