Prove the following using mathematical induction. a. For sets, (B1 B2 n ... n Bn)' = (B'₁ U B'2 U ... U B'n) b. For all positive integers n, 12 +2² + 3² + ... + n² = c. For all positive integers n, n(n+1)(2n+1) 6 - 1 + 3 + 5 + ... + (2n − 1) = n² d. For all positive integers n, + 1 1-2-3-4 n + + + = n(n + 1) n+1