Defining a constant in Mathematica

by ToxicBug
Tags: constant, defining, mathematica
 P: 85 Hello, I've been breaking my head over this for a couple hours now. I'm trying to find the expected value of a Gumbel distribution. Integrate[ y*E^(-((y - a)/b))*E^(-E^(-((y - a)/b)))/b, {y, -Infinity, Infinity}, Assumptions -> b > 0] If I set a = 2 and b = 5, it works. Otherwise it gives me a very complicated expression. I've tried SetAttributes[a, Constant], but it doesn't do the trick. Anyone know how can I solve this?
 Sci Advisor HW Helper P: 4,300 Try giving it some information about a, like Assumptions -> b > 0 && Element[a, Reals]