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CUET · MATHS · PYQ PAPER 2025

\(\sin ^{-1}\left(\cos \frac{3 \pi}{5}\right)\) equals

  1. A \(\frac{3 \pi}{5}\)
  2. B \(-\frac{\pi}{10}\)
  3. C \(\frac{\pi}{10}\)
  4. D \(-\frac{3 \pi}{10}\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(-\frac{\pi}{10}\)

Step-by-step Solution

Detailed explanation

\(\sin ^{-1}\left(\cos \frac{3 \pi}{5}\right)\) \( = \sin ^{-1}\left(\sin \left(\frac{\pi}{2} - \frac{3 \pi}{5}\right)\right)\) \( = \sin ^{-1}\left(\sin \left(\frac{5 \pi - 6 \pi}{10}\right)\right)\) \( = \sin ^{-1}\left(\sin \left(-\frac{\pi}{10}\right)\right)\)…