Use mathematical induction to prove each of the following: (a) For each natural number n, 2 + 5 + 8 +...+ (3n - 1) = n(3n + 1)/2. (b) For each natural number n, 1 + 5 + 9 +...+ (4n - 3) = n (2n - 1). (c) For each natural number n, 1^3 + 2^3 + 3^3 +...+ n^3 = [n(n + 1)/2]^2