Question

Упростите выражение 1-sin^2a / cos^2a-sin^2a

Answer 1

$\displaystyle\frac{1-\sin^2\alpha }{\cos^2\alpha }-\sin^2\alpha = \frac{\cos^2\alpha }{\cos^2\alpha }-\sin^2\alpha =1-\sin^2\alpha =\cos^2\alpha$