4. a) Determine whether Rolle's Theorem can be applied to f (x) = 1-x2 . [-2,2]. (Enter your answers using interval notation. If no answer exists write DNE) (5 points) b) If Rolle's Theorem can be applied, find all values of c in the open interval (a, b) such that f'(c) = 0. If Rolle's Theorem cannot be applied, explain why not. (If the theorem cannot be applied, enter NA) (5 points)