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If cosalpha+cosbeta = 0=sinalpha+sinbeta...

If `cosalpha+cosbeta = 0=sinalpha+sinbeta`, then `cos2alpha+cos2beta` is equal to

A

`-2 sin (alpha+beta)`

B

`-2 cos (alpha+beta)`

C

`2 sin (alpha+beta)`

D

`2 cos (alpha+beta)`

Text Solution

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The correct Answer is:
B
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