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If A=sin(2pi)/(7)+sin(4pi)/(7)+sin(8pi)/...

If `A=sin(2pi)/(7)+sin(4pi)/(7)+sin(8pi)/(7)` and `B=cos(2pi)/(7)+ cos(8pi)/(7 )` then `sqrt(A^(2)+B^(2))` is equal to

A

1

B

`sqrt(2)`

C

`2`

D

`sqrt(3)`

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The correct Answer is:
D
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