Answer the following question by writing codes in R. The answer can only be shown in R codes. (a) Write a function to compute the kth term in k=0 (-1) k ||a||2k+2 r(+) r(k + /3) k! 2k (2k + 1) (2k + 2) T(k+/+1) where d 1 is an integer, a is a vector in Rd, and || || denotes the Euclidean norm. Perform the arithmetic so that the coefficients can be computed for (almost) arbitrarily large k and d. (This sum converges for all a Rd). (b) Modify the function so that it computes and returns the sum. (c) Evaluate the sum when a = (1, 2)T. Results need to be shown in R Codes.