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The value of cos""(pi)/(7)+cos""(2pi)/(...

The value of `cos""(pi)/(7)+cos""(2pi)/(7)cos""(3pi)/(7)+cos""(4pi)/(7)+cos""(5pi)/(7)+cos""(6pi)/(7)+cos""(7pi)/(7)` is

A

1

B

-1

C

0

D

none of these

Text Solution

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The correct Answer is:
B
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