Объяснение:
1. sin(π\2-α)-cos(π-α)=cosα+cosα=2cosα
2. (cosβ+sinβ)²+(sinβ-cosβ)²=cos²β+2cosβsinβ+sin²β+sin²β-2sinβcosβ+cos²β=
=2cos²β+2sin²β=2
3. (1-cosα)\sinα+(sinα\(1-cosα))=((1-cosα)²+sin²α)\(sinα(1-cosα))=(2-2cosα)\(sinα(1-cosα))=2\sinα
