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Let cos(alpha+beta)""=4/5 and let sin (a...

Let `cos(alpha+beta)""=4/5` and let `sin (alpha+beta)""=5/(13)` where `0lt=alpha,betalt=pi/4` , then `t a n""2alpha=`

A

`25/16`

B

`56/33`

C

`19/12`

D

`20/7`.

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