Question

Prove This :

sin(A+B)+sin(A−B)=2sinA⋅cosB​

Answer 1

We know

sin (A + B) = sin A cos B + cos A sin B

sin (A - B) = sin A cos B - cos A sin B

(A + B) + sin (A - B)

= sin A cos B + cos A sin B + sin A cos B - cos A sin B

= sin A cos B + sin A cos B

= 2 sin A cos B