a) Give a recursive definition for the set of all strings of a's and b's where all the strings contain no more than two a's. (Assume, S is the set of all strings of a's and b's. Then S = {λ, a, aa, b, bb, ba, ab, bba, baa, ...}).
b) Give a recursive definition for the set of all strings of 'a's and 'b's that end with an 'a'. (Assume, S is the set of all strings of a's and b's. Then S = {a, aa, ba, aaa, aba, bba, baa, ...}).