Question

ПОМОГИТЕ!!Упростите выражения

Answer 1

$1)tg(-alpha)*Cosalpha+Sinalpha=-frac{Sinalpha }{Cosalpha }*Cosalpha+Sinalpha=-Sinalpha+Sinalpha=0\\2)frac{Ctg(-alpha)*Sinalpha}{Cosalpha}=frac{-frac{Cosalpha }{Sinalpha}*Sinalpha }{Cosalpha }=frac{-Cosalpha }{Cosalpha}=-1$

$3)Cos^{2}alpha*tg^{2}(-alpha)-1=Cos^{2}alpha *frac{Sin^{2}alpha}{Cos^{2}alpha  }-1=Sin^{2}alpha-1=-Cos^{2}alpha$

$4)frac{1-tg(-alpha)}{Sinalpha+Cos(-alpha)} =frac{1+frac{Sinalpha }{Cosalpha}}{Sinalpha+Cosalpha}=frac{Sinalpha+Cosalpha}{Cosalpha*(Sinalpha+Cosalpha)}=frac{1}{Cosalpha }$