Suppose the joint pdf of lifetimes of a certain part and a spare is given by
f(x, y) = e-(x + y); 0 < x < inf, 0 < y < inf
and zero otherwise. Find each of the following:
(a) The marginal pdf's, f1(x) and f2(y).
(b) The joint CDF, F(x, y)
(c) P[X > 2].
(d) P[X < Y].
(e) P[X + Y > 2].
(f) Are X and Y independent?