the joint density of X and Y is given by
f(x,y)= (e^-(x/y)*e^-y)/y 0 <x < inf , 0 < y < inf
so i worked out the conditional density function=
(e^-x/y )/y (confirmed to be correct)
now i need to integrate from 0 to infinity integral [x*(e^-x/y )/y dx] right???
i'm trying to integrate by parts
I cant show this to = y