Question

решите tga*sin*(-a)-cos(-a)

Answer 1

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