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The value of "cos"(2pi)/(7)+"cos"(4pi)/(...

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

A

1

B

`-1`

C

`1//2`

D

`-3//2`

Text Solution

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The correct Answer is:
d
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