Question

HEY I HAVE AN AP CALCULUS QUESTION

Which of the following statements is/are true?

1. If f '(c) = 0, then f has a local maximum or minimum at x = c.
2. If f is continuous on [a, b] and differentiable on (a, b) and f '(x) = 0 on (a, b), then f is constant on [a, b].
3. The Mean Value Theorem can be applied to f(x) = 1/x2 on the interval [−1, 1].

Answer 1

I say 1 & 3 are true, but not sure