2. (25) Let X and Y are two random variables with the joint PDF is given as fxy(x, y) = 12e-1(x+y), 1 > 0,x >0,y>0. (a) (10 points) Derive the marginal PDFs fx(x) and fr(y). (b) (10 points) Determine E[X|Y = y] and E [Y[X = x]. (c) (5 points) Can you comment on the independence between X and Y