Suppose the random variable X has PDF fx(x) = >e- for x 2 0. A) Calculate the first and second moments, E[X] and E[X2]. B) Derive a formula for the n'th moment E[X"], n = 2, 3.... C) Find o(s) = Eles ] stating values of s for which o(s) converges. D) Evaluate o (s) s o and comment on the result in light of part (a)