Question

2sinAsinB=cos(A-B)-cos(A+B)

Answer 1

\[\cos (A-B)-\cos (A+B)=\]
\[\cos A \cos B+\sin A \sin B-(\cos A \cos B-\sin A \sin B)\]

Answer 2

You can finish it

Answer 3

2sinAsinB ?

Answer 4

What were you supposed to show that it is equal to?