N N N + > 4 16 4k (30 pts) For each of the following sum, find the closed form expression and determine the minimum integer c > 0, where the sum is no more than cN for (a) and cN for (b). a. N + + where k = [log4N]. b. 2/2 (N 2i + 2). Note: You are not required to prove your closed forms by induction but you need to show the steps through which you derive them and state which known closed forms of summations you are using