Question

упростите выражение

Answer 1

$sin(5pi -alpha )*cos(frac{3pi} {2} +alpha)-ctg(frac{pi} {2}- alpha)+tg( alpha -pi)=$$=sin(pi -alpha )*cos(frac{3pi} {2} +alpha)-ctg(frac{pi} {2}- alpha)-tg(pi-alpha)= sinalpha*sinalpha-tgalpha+tgalpha=$$=sinalpha*sinalpha=sin^2alpha$