Again, MathML is not supported in ePUB at the moment. However, you can use a trick to include it. If you are lucky, it will render on your device. I would not get your hopes up, I think most readers will not support it. You could be lucky though.
I entered a search in google and the first hit was from Liza Daly describing the process. Link is
here. For your information, the search I fed into Google was 'mathml epub'.