* ! Exercise 2.2.9: Let A-(Q, . .qo, {91}) be a DFA, and suppose that for all a in we have (q, a)-&qf, a). a) Show that for all wwe have (,W) = 5(91, u). b) Show that if a is a nonempty string in L(A), then for all k >0, r* (i.e., r written k times) is also in L(A)