Question

Упростите выражение 8sin^2a/1+tg^2a

Answer 1

$\frac{8Sin^{2}\alpha}{1+tg^{2}\alpha}=\frac{8Sin^{2}\alpha}{\frac{1}{Cos^{2}\alpha}}=8Sin^{2}\alpha Cos^{2}\alpha=2*(4Sin^{2}\alpha Cos^{2}\alpha)=2Sin^{2}2\alpha$