Question

Let f(x) = x³ – 6x² + 9x + 18, then f(x) is strictly increasing in ______.

Options

• `(- ∞, 1)`

• `(3, ∞)`

• `(- ∞, 1) ∪ (3, ∞)`

• (1, 3)

Answer 1

Let f(x) = x³ – 6x² + 9x + 18, then f(x) is strictly increasing in `underlinebb((- ∞, 1) ∪ (3, ∞)`.