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CUET · MATHS · PYQ PAPER 2025

The function f(x) = \(\log _e\)(sin x), x ∈ (0,π) is
(A) strictly increasing on \(\left(0, \frac{\pi}{2}\right)\)
(B) strictly decreasing on \(\left(0, \frac{\pi}{2}\right)\)
(C) strictly increasing on \(\left(\frac{\pi}{2}, \pi\right)\)
(D) strictly decreasing on \(\left(\frac{\pi}{2}, \pi\right)\)
(E) strictly increasing on \((0, \pi)\)
Choose the correct answert from the option given below :

  1. A (A) and (D) only
  2. B (B) and (C) only
  3. C (A), (D) and (E) only
  4. D (B), (D) and (E) only
Verified Solution

Answer & Solution

Correct Answer

(A) (A) and (D) only

Step-by-step Solution

Detailed explanation

\(f(x) = \log_e(\sin x)\) \(f'(x) = \frac{1}{\sin x} \cdot \cos x = \cot x\) For \(x \in \left(0, \frac{\pi}{2}\right)\), \(\cot x > 0\). So, \(f(x)\) is strictly increasing. For \(x \in \left(\frac{\pi}{2}, \pi\right)\), \(\cot x Thus, (A) and (D) are correct.