Выполни задание

Докажи тождество:

1. \({\sin (\alpha+\beta)-\sin \alpha \cos^3 \beta \mathrlap{\:-}}\) \({-\cos \alpha \sin^3 \beta =\sin \beta \cos \beta \cos (\alpha-\beta)}\) ;

2. \({\cos (\alpha-\beta)-\sin \alpha \sin^3 \beta \mathrlap{\:-}}\) \({-\cos \alpha \cos^3 \beta =\sin \beta \cos \beta \sin (\alpha+\beta)}\) .