To get MathJax to work in Blogger, just go to your Blogger account, click "Design" (top right of the page), and then "Edit HTML". After the first <head> you see, paste
<script src='http://cdn.mathjax.org/mathjax/latest/MathJax.js' type='text/javascript'>
MathJax.Hub.Config({
HTML: ["input/TeX","output/HTML-CSS"],
TeX: { extensions: ["AMSmath.js","AMSsymbols.js"],
equationNumbers: { autoNumber: "AMS" } },
extensions: ["tex2jax.js"],
jax: ["input/TeX","output/HTML-CSS"],
tex2jax: { inlineMath: [ ['$','$'], ["\\(","\\)"] ],
displayMath: [ ['$$','$$'], ["\\[","\\]"] ],
processEscapes: true },
"HTML-CSS": { availableFonts: ["TeX"],
linebreaks: { automatic: true } }
});
</script>
And that's all! Now you can use standard LaTeX commands to format mathematical text. For example, the radiative transfer equation along a ray (e.g. see the lecture notes of Rob Rutten, Eq.2.24) can be written as:
\frac{\mathrm{d}I_{\nu}}{\alpha_{\nu}\mathrm{d} s} = S_{\nu} - I_{\nu}
and appears as: $$ \frac{\mathrm{d}I_{\nu}}{\alpha_{\nu}\mathrm{d} s} = S_{\nu} - I_{\nu} $$
