Упростить1)1+sin(-a)/cos(-a) - tg(-a)=2) cos^2(-a)-cos^4(-a)/sin^2(-a) =a-альфаЗаранее...

$1) = \frac{1-sin \alpha }{cos \alpha }-(-tg \alpha )= \frac{1}{cos \alpha }- \frac{sin \alpha }{cos \alpha }+tg \alpha =\frac{1}{cos \alpha }-tg \alpha +tg \alpha =\frac{1}{cos \alpha }$
$2)= \frac{cos^2 \alpha *(1-cos^2 \alpha )}{-sin^2 \alpha }= \frac{cos^2 \alpha* sin^2 \alpha }{-sin^2 \alpha }=-\frac{cos^2 \alpha* sin^2 \alpha }{sin^2 \alpha }=-cos^2 \alpha$