Let (a) Show that Q is a probability function. That is, show that the terms are non-negative

Question:

Let

2 for k = 0, 1, 2, .... 3k+1 Q(k) = %| (a) Show that Q is a probability function. That is, show that the terms are non-negative and sum to 1.
(b) Let X be a random variable such that P(X = k) = Q(k), for k = 0, 1, 2, . . . . Find P(X > 2) without summing an infinite series.