enter answer comma separated, interval notation

Question

The graph of f is shown in the figure.

(a)

For which values of x is f '(x) zero? (Enter your answers as a comma-separated list.)

x = 

 

For which values of x is f '(x) positive? (Enter your answer using interval notation.)

 

For which values of x is f '(x) negative? (Enter your answer using interval notation.)

 

Answer 1

f'(x) = 0 at x = -2, 2

f'(x) is positive where the slope is increasing. (-∞,-2) and (2,∞)

f'(x) is negative where the slope is decreasing. (-2,2)