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If 2 cos theta=x+(1)/(x), find the value...

If `2 cos theta=x+(1)/(x)`, find the value of `2cos 3 theta`

A

`x^3+1/x^3`

B

`x^2+1/x^2`

C

`x^3-1/x^3`

D

`sqrt(x+1/x)`

Text Solution

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The correct Answer is:
A
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