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If x+y=z then cos^2 x+cos^2 y+cos^2 z-2c...

If `x+y=z` then `cos^2 x+cos^2 y+cos^2 z-2cosx cosy cosz=`

A

`cos^(2)z`

B

`sin^(2)z`

C

0

D

1

Text Solution

Verified by Experts

The correct Answer is:
D
`cos^(2)x+cos^(2)y+cos^(2)z-cosz(cos(x+y)+cos(x-y))`
`=cos^(2)x+cos^(2)y+cos^(2)z-cos^(2)z-cos(x+y).cos(x-y)=1`
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