Question 6 [18 marks] The joint probability density function of X and Y is given by fxy(x, y) = c(y- x)ev, -y0, 0 , otherwise. a. Show that c = 2. b. Find the marginal probability density functions fx(x) and fy(y). c. Are X and Y independent? Justify your answer. d. Find the conditional probability density functions fxy(xly) and fyx(yla). e. Verify the identity E(X) = E(E(X|Y))