1. The problem statement, all variables and given/known data Find the value of k that makes this a probability density function. The question does not specify whether X and Y are independent or dependent. That is actually another part this question. 2. Relevant equations Let X and Y have a joint density function given by f(x,y) =e^(-kX), 0<=X<inf, 0<=Y<=1, k is a constant, and 0 elsewhere 3. The attempt at a solution I need quite a bit of direction with this question, I have no idea where to start.