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In Delta ABC, if the sides a,b,c are in ...

In `Delta ABC`, if the sides a,b,c are in geometric progression and the largest angle exceeds the smallest angle by `60^@`, then `cos B` .

A

` (sqrt(13) + 1)/( 4 )`

B

` ( 1- sqrt(13))/(4) `

C

` 1`

D

` ( sqrt(13)-1)/( 4) `

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The correct Answer is:
D
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