1. The problem statement, all variables and given/known data ∞ ∫ e^(-y/θ) dy 0 2. Relevant equations The directions say evaluate when theta>0. 3. The attempt at a solution I have been integrating by using u of substitution and been getting -θ*e^(-y/θ) and evaluating from 0 to ∞ and getting the answer as undefined. I need help with evaluating the integral. Please help. Thanks.