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Prove that cos^(4)pi/8+cos^(4)(3pi)/(8...

Prove that
`cos^(4)pi/8+cos^(4)(3pi)/(8)+cos^(4)(5pi)/8+cos^(4)(7pi)/8=3/2`

A

`(3)/(2)`

B

`-(2)/(3)`

C

`-1`

D

1

Text Solution

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The correct Answer is:
A
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LUCENT PUBLICATION-ADVANCED TRIGONOMETRIC IDENTITIES-EXERCISE 13A
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