2 Problem 2 . Part 1 (3 points): Prove by induction that 1 (k-1)2*+1+2 . Part 2 (4 points): Prove that h" (n") . Part 3 (3 points): what is ogl()4i equal to in -notation? (No formal proof necessary, just a brief explanation.) HINT: use the formula for geometric sum: :-1 This is generally a very useful formula. rk = (rk-1)/(r-1)