Дано 2sin^2a/tga(cos^2a-sin^2a)=tg2a

[latex] \frac{2sin ^{2} \alpha }{tg \alpha *( cos^{2} \alpha - sin^{2} \alpha )} =tg2 \alpha [/latex] [latex] \frac{ 2sin^{2} \alpha }{ \frac{sin \alpha }{cos \alpha } *cos2 \alpha } = \frac{2 sin^{2} \alpha *cos \alpha }{sin \alpha *cos2 \alpha } = \frac{2sin \alpha *cos \alpha }{cos2 \alpha } = \frac{sin2 \alpha }{cos2 \alpha } =tg2 \alpha tg2 \alpha =tg2 \alpha [/latex]