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If sin 2 beta is the geometric mean betw...

If `sin 2 beta` is the geometric mean between `sin alpha and cos alpha,` then `cos 4 beta` is equal to

A

`2sin^(2)((pi)/(4)-alpha)`

B

`2cos^(2)((pi)/(4)-alpha)`

C

`2cos^(2)((pi)/(2)+alpha)`

D

`2sin^(2)((pi)/(4)+alpha)`

Text Solution

Verified by Experts

The correct Answer is:
A
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