If x+y+z =180^(@), then cos 2x+ cos 2y ...

If `x+y+z =180^(@), ` then `cos 2x+ cos 2y - cos 2z` is equal to

A

4 sinx siny sinz

B

1-4 sinx siny cosz

C

4 sinx siny sinz-1

D

cosx cosy cosz

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