ПОМОГИТЕЕЕ 1. (tg a + ctg a) * sin a * cos a 2. sin^2 a * cos^2 a (tg^2 a + ctg^2 a + 2)

[latex](tg \alpha +ctg \alpha )\cdot \sin \alpha \cos \alpha =tg \alpha \sin \alpha \cos \alpha +ctg \alpha \sin \alpha \cos \alpha =\\ \\ =\sin^2 \alpha +\cos^2 \alpha =1[/latex] [latex]\sin^2 \alpha \cos^2 \alpha (tg^2 \alpha +ctg^2 \alpha +2)=\sin^2 \alpha \cos^2 \alpha (tg \alpha +ctg \alpha )^2=\\ \\ =(tg \alpha \sin \alpha \cos \alpha +ctg \alpha \sin \alpha \cos \alpha )^2=(\sin^2 \alpha +\cos^2 \alpha )^2=1^2=1[/latex]