[ 10 points] Consider the functionsf(x, y, z, w)-2 (1, 3, 4, 5, 6, 8, 9, 12, 13, 15) and g(r, y, z, w)- 11 (0, 4, 5, 7, 8, 10, 1 1, 13, 15). Let/' denote the complement off. (a) (5 points) Find the minimum sum of products expression for the function f'+ g. (b) (5 points) Indicate the prime implicants and essential prime implicants off'+ g. 1