Trigonometry Identities - Sum to Product to Identity (Greek Letter)

Question

Complete the sum to product identity for this expression

$$	ext{cos}{(	heta)}-	ext{cos}{(\beta)}$$

Accepted Answer

$$=-2 	ext{sin}{( \frac{(	heta + \beta)}{2})}   	ext{sin}{( \frac{(	heta - \beta)}{2})}$$

Answer

$$=2 	ext{sin}{( \frac{2}{(	heta + \beta)})}   	ext{cos}{( \frac{(	heta - \beta)}{2})}$$