AP 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 :
- A \(\frac{1}{16}\)
- B \(\frac{1}{8}\)
- C \(\frac{1}{12}\)
- D \(\frac{1}{4}\)
Answer & Solution
Correct Answer
(A) \(\frac{1}{16}\)
Step-by-step Solution
Detailed explanation
\(\cos \frac{2 \pi}{15} \cos \frac{4 \pi}{15} \cos \frac{8 \pi}{15} \cos \frac{14 \pi}{15}\) \(=\cos 24^{\circ} \cos 48^{\circ} \cos 96^{\circ} \cos 168^{\circ}\) \(=-\cos 12^{\circ} \cos 24^{\circ} \cos 48^{\circ} \cos 96^{\circ}\)…
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