Question

Find the interval in which the function f(x) = x⁴ – 4x³ + 10 is strictly decreasing.

Answer 1

We have f(x) = x⁴ − 4x³ + 10

⇒ f'(x) = 4x³ − 12x²

⇒ f'(x) = 4x² (x − 3)

For f(x) is strictly decreasing, we must have f'(x) < 0

Value of x is 0, 3

Strictly Decreasing (-∞, 0) ∪ (0, 3)