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If 7 theta = (2n +1) pi, where n = 0 , ...

If `7 theta = (2n +1) pi, ` where `n = 0 , 1, 2, 3, 4,5, 6` then on the basis of above information, answer the following questions
The equation whose roots are `cos pi//7 , cos 3pi//7, cos 5pi//7` is

A

`8x^(3) + 4x^(2)+4x+1=0`

B

`8x^(3) - 4x^(2)-4x+1=0`

C

`8x^(3) - 4x^(2)-4x-1=0`

D

`8x^(3) + 4x^(2)+4x-1=0`

Text Solution

Verified by Experts

The correct Answer is:
B
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