2.1.15. Let X1,X2 be two randomvariables with joint pdff(x1, x2) = x1 exp{-x2), for 0

2.1.15. Let Xl,X2 be two randomvariables with joint pdff(xl, x2) = xl expfx2), for 0 < xl < x2 < m, zero elsewhere. Determine the joint mgf ofXIX2. Does M(tl, t2) = M(tl, t2)?