यदि , tan A = x tan Bतो सिद्ध कीजिए कि -
` ( x+1) sin (A-B) = (x-1) sin (A+B)`

Explanation

` tan A = x tan B`
` rArr x = (tanA)/(tanB) = ((sin A)/(cosA))/((sinB)/(cosB)) = (sin A cos B)/ (sinB cosA)`
` (x+1)/(x-1) = ((sin A cos B)/(sin A cos B)+1)/((sin A cos B)/(sinB cos A )-1)`
` = (sin A cos B + sin Bcos A)/( sinA cos B - sin B cos A)`
` = (sin(A+B))/(sin(A-B))`
` rArr (x+1) sin (A-B) = (x-1) sin (A+B)`