Prove that, for all natural numbers n, E?_(2 r)3 = 2 n2(n + 1)2. Select the steps necessary for a proof by induction. Prove the base case when n = 1. Since the result is true for n = 1 and the k + 1 case is true assuming the O k th case is true the formula holds for all cases. O Prove the base case when n = 0. Assume the formula holds when n = k, that is 0 8 + 64 + 216 + ... + (2k) 3 = 2k2(k + 1)2 . Since the k + 1 case is true assuming the k th case is true the formula O holds for all cases. Show that 8 + 64 + 216 + ... + (2k) 3 + (2 (k + 1))3 = 2(k + 1)2(k+ 2)2 by assuming that 8 + 64 + 216 + ... + (2k)3 = 212(k + 1)2