Question

Упростить выражение. памагитииии

Answer 1

$frac{cos^2alpha-sin^2alpha-1}{(sinalpha+cosalpha)^2-1}=frac{cos^2alpha-sin^2alpha-(cos^2alpha+sin^2alpha)}{sin^2alpha+cos^2alpha+2*cosalpha*sinalpha-1}=frac{cos^2alpha-sin^2alpha-cos^2alpha-sin^2alpha}{1+2*cosalpha*sinalpha-1}=$$=frac{-2sin^2alpha }{2*cosalpha*sinalpha}=-frac{sinalpha }{cosalpha}=-tgalpha$