8.3.2 In the message transmission prob- lem, Problem 8.1.5, the PMF for the num- ber of transmissions when message i is re- ceived successfully is Pk (k) = [p (1 - p)^3-3 k < k < kai To k. {1,2...). otherwise. Let Ja K3-K2, the number of trans- missions of message 3; J = K2 - K1, the number of transmissions of message 2; and J = K, the number of transmissions of message 1. Derive a formula for Pa(j), the PMF of the number of transmissions of in- dividual messages.