a. Classify each of the following functions: i. f1 (x) : R - R defined by f1 (x) = 5x2 + 1 ii. f2 (z) : C - C defined by f2 (z) = 5z2 + 1 iii. f3 (n) : Z - Z defined by f3 (n) = 5n2 + 1 iv. f4 (x + yi) : C - C defined by f4 (x + yi) = (2 + 3x) +i(1 -2y) b. For the function f4 in part (a), give a formula for the inverse function g. g ( x + yi) = +