Question
Prove that the function f (x) = 4x3 – 6x2 + 3x + 12 is increasing on R
Solution
Here f (x) = 4x3 – 6x2 + 3x + 12 12 ∴ Df = R
f ' (x) = 12x2 – 12x + 3 = 3(2x – 1)2 4x + 1) = 3(2 x – 1)2 ≥ 0 ∀ x ∊ R
∴ f (x) is increasing on R.
