सिद्ध कीजिए कि
` ( cos (A -B)+sinA -cos (A+B))/(sin (A+B)+cos A - sin (A -B))= tan A.`

Explanation

` L.H.S = (cos(A-B) + sinA - cos (A+B))/(sin(A+B)+cos A - sin (A-B))`
` ( cos A cos B + sin A sin B) + sinA `
` = (-(cos A cos B - sin A sinB))/((sinA cos B + cos A sinB ) + cos A)`
` - ( sin A cos B - cos A sin B)`
` = (sin A + 2 sin A sin B )/(cos A + 2 cos A sin B)`
` = (sin A( 1+ 2 sin B))/(cosA (1+2sinB))`
` = tan A = R.H.S`