How to Post Maths in Blogspot: MathJax & QuickLatex

Edit your template and add the following before the closing "head" tag:

<script type=\"text/x-mathjax-config\">
MathJax.Hub.Config({
  MMLorHTML: {
    prefer: {Firefox: \"HTML\"}
  }
});
</script>
<script type=\"text/javascript\" src=\"http://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML-full\"></script>

Then you just stick the TeX stuff in backslash square brackets for standalone formulae or backslash rounded brackets for in text symbols.

To get graphics you need to use Quicklatex. You need to drop down the choose options box on that page and then insert this text to activate the Tikz graphics package, with the tikz library that lets you calculate co-ordinates using algebra:

\usepackage{tikz}
\usetikzlibrary{calc}

You then get the URL of an image which you can stick in your blog.