1) sin480=sin(360+120)=sin(180-60)=sin60=V3/2
2) cos(-570)=cos(540+30)=-cos30=-V3/2
3) tg(-750)=-tg(720+30)=-tg30=-1/V3
4) ctg495=ctg(540-45)=-ctg45=-1
1) sin480=sin(360+120)=sin(180-60)=sin60=V3/2
2) cos(-570)=cos(540+30)=-cos30=-V3/2
3) tg(-750)=-tg(720+30)=-tg30=-1/V3
4) ctg495=ctg(540-45)=-ctg45=-1