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If cos 5theta=a cos theta + b cos^(3)the...

If `cos 5theta=a cos theta + b cos^(3)theta+c cos^(5) theta+d`, then

A

`a + b + c = 2`

B

`a + b + c + d = 1`

C

`b = - 20`

D

None of these.

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The correct Answer is:
B
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