Q.4) For the following bivariate Probability density function : f(x, y)=\left\{\begin{array}{ll} \frac{c}{5} e^{-\lambda y} & \mid \geqslant x>0, \quad y \geqslant 0 \\ 0 & \text { otherwise } \end{array}\right.

a.) Assume X and Y are independent; calculate Constant C such that f(x,y) is a valid joint PDF b.) Find the Marginal Probability Distribution function of X. c.) Find the Marginal Cumulative Distribution of Y. d.) Find E[XY].