Part Il: Functions (50 pt.) 1. (50 pt., 10 pt. each) For each of the following functions, determine whether the function is: Injective (one-to-one) .Surjective (onto) Bijective. Invertible. Justify your answers a. f: R+ ? R+ such that f(x) = 1. b. f: R-R such that f(x) |x/2]. c. f: R ? R such that f(x) = 1x1. d. f: R-(0) ? R such that f(x)--. e. f.z z z such that f (x,y)-x + y