MathJax Test

I've been struggling to include Mathjax in Blogger properly to write proper mathematical equations. A lot of people saying "paste this here", but this is the only one that worked:

http://holdenweb.blogspot.com/2011/11/blogging-mathematics.html

So here's a little test:

$x^2$

The Fourier Transform is given as:

$F(k) = \int^{\infty}_{-\infty} f(t) e^{-2 \pi k t} dt$

 ...and I happy.

For Blogger, you need to open the Theme, then Cutomize->Edit HTML 

Then copy and paste the code kindly provided in the link above, which I have copied below. Use Ctrl-F to find < /head >. You need to paste it before the < /head >
<script type="text/x-mathjax-config"> MathJax.Hub.Config({tex2jax: {inlineMath: [['$','$'], ['\\(','\\)']]}}); </script> <script src="http://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML" type="text/javascript"> </script>