Problem 9: Decide if the statements below are true or false. In each part, give explanations/counter-examples no explanation or no counter-example = no credit). (a) If a function f is decreasing for a c, then it has a local minimum point at x = c. (b) If a point P is critical for a function f, then f'(P) = 0. (c) If the radius of a circle is increasing at a constant rate, then its area is also increasing at a constant rate. (d) If 3