Answer
The formula $\sin \alpha +\sin \beta =2\sin \frac{\alpha +\beta }{2}\cos \frac{\alpha -\beta }{2}$ can be used to change the sum of two sines into the product of sines and cosines expressions.
Work Step by Step
$\sin \alpha +\sin \beta =2\sin \frac{\alpha +\beta }{2}\cos \frac{\alpha -\beta }{2}$
Thus, the above identity sum to product formula reflects that the sum of two sines is equal to the twice the product of the sines and cosines expression.
