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← JEE Main 2026 · 8 Apr · Shift 2
MathematicsSingle correct+4 / -1Question 13 of 75

JEE Main 2026 · 8 Apr · Shift 2, Mathematics question 13

For the function f(x)=esin⁡∣x∣−∣x∣f(x)=e^{\sin|x|}-|x|, x∈Rx\in\mathbf R, consider the following statements :

Statement I : ff is differentiable for all x∈Rx\in\mathbf R.

Statement II : ff is increasing in (−π,−π2)\left(-\pi,-\dfrac\pi2\right).

In the light of the above statements, choose the correct answer from the options given below :

Choose one option
Answer and worked solution

Official answer: A

At x = 0.

  • For x>0x>0: f=esin⁡x−xf=e^{\sin x}-x, f′=cos⁡x esin⁡x−1→0f'=\cos x\,e^{\sin x}-1\to0.
  • For x<0x<0: f=e−sin⁡x+xf=e^{-\sin x}+x, f′=1−cos⁡x e−sin⁡x→0f'=1-\cos x\,e^{-\sin x}\to0.

Both one-sided derivatives are 0, and f is smooth elsewhere: I is true.

On (−π,−π2)(-\pi,-\tfrac\pi2). cos⁡x<0\cos x<0, so f′=1−cos⁡x e−sin⁡x>0f'=1-\cos x\,e^{-\sin x}>0: increasing. II is true.

(A)