(a+b+c)(cosA+cosB+cosC)...

`(a+b+c)(cosA+cosB+cosC)`

A

`sum a sin^(2).(A)/(2)`

B

`sum a cos^(2).(A)/(2)`

C

`2 sum a sin^(2).(A)/(2)`

D

`2 sum a cos^(2).(A)/(2)`

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The correct Answer is:

D

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