Question

Using the definition of the derivative, find f'(x). Then find f'(-4), f'(0), and f'(4) when the derivative exists.

f(x) = 3x³ +5

Answer 1

f(x) = 3x³ + 5

f'(x) = 9x²

f'(-4) = 9(-4)² = 9(16) = 144

f'(0) = 0

f'(4) = 9(4²) = 9(16) = 144