Question

Тригонометрия (начальная)

Answer 1

(sin²a-2sinacosa+cos²a-sin²a-cos²a)/(sin²a-cos²a-sin²a-cos²a) - tga=
=(-2sinacosa)/(-2cos²a) - tga=tga-tga=0
0=0

Answer 2

$frac{(sinalpha -cos alpha )^2-1}{sin^2alpha -cos^2alpha -1} + ctg( frac{3pi}{2}+alpha)=0 \ frac{sin^2alpha -2sinalpha cosalpha +cos^2alpha -1}{sin^2alpha-cos^2alpha -1 } -tgalpha= frac{-2sinalpha cosalpha }{-2cos^2alpha } -tgalpha= \ =tgalpha -tgalpha=0$