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If alpha,beta and gamma are angles made ...

If `alpha,beta and gamma` are angles made by a line with coordinate axes such that `alpha=beta=2gammaandanglealpha` is acute, then `cos alpha`=

A

`(sqrt(17)-1)/(8)`

B

`(sqrt(17)+1)/(8)`

C

`(-sqrt(17)+1)/(8)`

D

none of these

Text Solution

Verified by Experts

The correct Answer is:
A
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