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sum (r=1) ^(10) cos ^(3) "" (r pi)/(3) =...

`sum _(r=1) ^(10) cos ^(3) "" (r pi)/(3) =`

A

`-1/8`

B

`-7/8`

C

`-9/8`

D

`1/8`

Text Solution

Verified by Experts

The correct Answer is:
C
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