NTA Abhyas JEE Main2020MathematicsApplication of DerivativesPractice
The function f x = x 1 + | x | is
Options
- Astrictly increasing
- Bstrictly decreasing
- Cneither increasing nor decreasing
- Dnot differentiable at x = 0
Correct answer
A. strictly increasing
Step-by-step solution
Given, f x = x 1 + | x | ∴       f ′ x = 1 + x . 1 - x . x x 1 + x 2 = 1 1 + x 2 > 0   ∀ x ∈ R ⇒       f ( x ) is strictly increasing