ExamBro
ExamBro
TS EAMCET · Maths · Trigonometric Ratios & Identities

The value of \(\cos \frac{2 \pi}{15} \cos \frac{4 \pi}{15} \cos \frac{8 \pi}{15} \cos \frac{14 \pi}{15}\) is :

  1. A \(\frac{1}{16}\)
  2. B \(\frac{1}{8}\)
  3. C \(\frac{1}{12}\)
  4. D \(\frac{1}{4}\)
Verified Solution

Answer & Solution

Correct Answer

(A) \(\frac{1}{16}\)

Step-by-step Solution

Detailed explanation

\(\cos \frac{2 \pi}{15} \cos \frac{4 \pi}{15} \cos \frac{8 \pi}{15} \cos \frac{14 \pi}{15}\) \(=\cos 24^{\circ} \cos 48^{\circ} \cos 96^{\circ} \cos 168^{\circ}\) \(=-\cos 12^{\circ} \cos 24^{\circ} \cos 48^{\circ} \cos 96^{\circ}\)…