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If cos(A-B)=3/5 and tanAtanB=2 then...

If `cos(A-B)=3/5` and `tanAtanB=2` then

A

`cosA cos B = 1/5`

B

`sin A sin B=-2/5`

C

`cosA cos B=-1/5`

D

`sin A sin B= 1//5`

Text Solution

Verified by Experts

The correct Answer is:
A
(1) `cot(A-B)=(3)/(5)`
or `5cosA cosB+5sin A sin B=3`
From the second relation, we have
`sin A sin B=2cos A cos B`
`rArr cosA cos B=(1)/(5)` and `sin A sin B=(2)/(5)`
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