Question

Решите tga*sin*(-a)-cos(-a)

Answer 1

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