Question

Find the intervals in which the function f given by f(x) = x² – 4x + 6 is strictly increasing:

Options

• (– ∞, 2) ∪ (2, ∞)

• (2, ∞)

• (−∞, 2)

• (– ∞, 2] ∪ (2, ∞)

Answer 1

(2, ∞)

Explanation:

f(x) = x² – 4x + 6

f'(x) = 2x – 2

let f'(x) = 0 ⇒ x = 2

as f'(x) > 0 ∀ x ∈ (2, ∞)

f(x) is strictly increasing in (2, ∞)