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If A+B+C=180^(@) " then " cos A - cos B+...

If `A+B+C=180^(@) " then " cos A - cos B+ cos C = `

A

`-1+4 sin""(A)/(2)sin""(B)/(2) sin""(C)/(2)`

B

`-1+4 cos""(A)/(2)cos""(B)/(2)sin""(C)/(2)`

C

`-1+4 cos""(A)/(2)cos""(B)/(2)cos""(C)/(2)`

D

`-1+4 cos""(A)/(2)sin""(B)/(2)cos""(C)/(2)`

Text Solution

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The correct Answer is:
D
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DIPTI PUBLICATION ( AP EAMET)-TRIGONOMETRIC RATIOS AND IDENTITIES -EXERCISE 1 E ( TRIGONOMETRIC IDENTITIES )
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