Simpson's Formulas/Cosine by Sine

Theorem

 * $\cos \alpha \sin \beta = \dfrac {\sin \left({\alpha + \beta}\right) - \sin \left({\alpha - \beta}\right)} 2$

where $\cos$ denotes cosine and $\sin$ denotes sine.

Also reported as
This result can also sometimes be seen as:


 * $2 \cos \alpha \sin \beta = \sin \left({\alpha + \beta}\right) - \sin \left({\alpha - \beta}\right)$