Hey can someone tell me the value of the integral of X^2 exp (-aX^2) dx from zero to infinity. I have the general solution from a table of integrals but since the upper limit is infinity, I can't really plug these numbers in. Can't find it in a table of integrals anywhere? If anyone has the answer it would be really great as I could then continue on in my P-chem homework. I also know how to do this with integration by parts, but there is the whole catch of infinity as the upper limit, anything beyond doing integration is past my personal education and capabilities.