Explaining maths

Since I can now use MathJax here, but not on my WordPress blog, I am going to transfer some of my recent posts over from WordPress, using MathJax here. But first I have a lot of marking to do!

 Following suggestions on  http://holdenweb.blogspot.com/2011/11/blogging-mathematics.html \[\int_0^\infty \exp(-x) \mathrm{d} x = \left[-\mathrm{e}^{-x}\right]_{0}^\infty = 1\,.\] Looks OK!