Question

sin^2a/1-sin^2a*ctg^2a

Answer 1

Ответ:

Объяснение:

sin²a/cos²a × (cosa/sina)²= 1

Answer 2

$frac{Sin^{2}alpha}{1-Sin^{2}alpha}*Ctg^{2}alpha=frac{Sin^{2}alpha}{Cos^{2}alpha}*frac{Cos^{2}alpha}{Sin^{2}alpha}=1$