The value of cos ( 14 π ) cos ( 14 3 π ) cos ( 14 5 π ) is

Put x = − 1 ⇒ cos ( 14 π ) cos ( 14 3 π ) cos ( 14 5 π ) = 8 7

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MathematicsTrigonometric Ratios & IdentitiesMiscellaneous/MixedMedium2 minQB

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Passage / Comprehension

Let $cos \frac{π}{7}, cos \frac{3 π}{7}, cos \frac{5 π}{7}$ are the roots of equation $8 x^{3} - 4 x^{2} - 4 x + 1 = 0$

The value of $cos (\frac{π}{14}) cos (\frac{3 π}{14}) cos (\frac{5 π}{14})$ is

Answer:

Solution:

Put $x = - 1 \Rightarrow cos (\frac{π}{14}) cos (\frac{3 π}{14}) cos (\frac{5 π}{14}) = \frac{7}{8}$

Stream:JEESubject:MathematicsTopic:Trigonometric Ratios & IdentitiesSubtopic:Miscellaneous/Mixed

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