2. For each of the following functions f A R, find f(A) and hence decide whether f (equivalently its range) has an upper bound, a lower bound, a maximum or a minimum. (a) f(x) = x, A = (3, 2). (b) f(x) = x, A = (3, 2) (c) f(x) = X 0 if x E Q if x # Q A = [0, a] where a > 0.