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In triangle ABC, prove that cos .(A)/(2)...

In triangle ABC, prove that `cos .(A)/(2)+cos.(B)/(2)+cos. (C)/(2) =4 cos .(pi-A)/(4)cos. (pi-B)/(4) cos.(pi-C)/(4)`

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The correct Answer is:
`=4 cos. (pi-A)/ (4) . Cos. (pi-B)/(4). Cos. (pi-C)/(4)=R.H.S`
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