Changing mathjax's font size

Question

I am using mathjax on my page, and i have read that this:

Answer 1

I tried numerous things, including modifying config/default.js

http://docs.mathjax.org/en/latest/options/index.html

or mathjax.js, none of them worked (I use Drupal 6 and therefore had to revert to MathJax 1.1)

Finally, based on Wojciech's answer, I found something that worked. Simply surround the Math code with a div like that:

\begin{equation} \frac{\partial e_b}{\partial x^b} =   \Gamma_{ab}^k  e_k   \end{equation}