Prove: $\sin (\alpha - \beta) = \sin \alpha \cos \beta - \sin \beta \cos \alpha$
This website has a lot of cool stuff about trigonometry.
https://trigonography.com/2015/09/28/angle-sum-and-difference-for-sine-and-cosine/
This website has a lot of cool stuff about trigonometry.
https://trigonography.com/2015/09/28/angle-sum-and-difference-for-sine-and-cosine/