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The value of cos ( pi //5) cos ( 2pi //5...

The value of `cos ( pi //5) cos ( 2pi //5) cos ( 4pi //5) cos ( 8pi //5)` is

A

`1//16`

B

0

C

`- 1//8`

D

`- 1//16`

Text Solution

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The correct Answer is:
D
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ML KHANNA-TRIGONOMETRY RATIOS AND IDENTITIES-MISCELLANEOUS EXERCISE (SELF ASSESSMENT TEST)
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  3. If theta and phi are angles in the first quadrant such that tan theta ...

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  16. If (sin^4x)/2+(cos^4x)/3=1/5t h e n tan^2x=2/3 (b) (sin^8x)/8+(cos^...

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