青岛晓寒
幼苗
共回答了15个问题采纳率:93.3% 举报
sin120°=sin(180°-60°)=sin60°
sin(-120°)=-sin120°=-sin60°
cos120°=cos(180°-60°)=-cos60°
cos(-120°)=cos120°=-cos60°
tan120°=tan(180°-60°)=-tan60°
tan(-120°)=-tan120°=tan60°
sin220°=sin(180°+40°)=-sin40°
sin(-220°)=-sin220°=sin40°
cos220°=cos(180°+40°)=-cos40°
cos(-220°)=cos220°=-cos40°
tan220°=tan(180°+40°)=tan40°
或者:tan220°=sin220°/cos220°=(-sin40°)/(-cos40°)=tan40°
tan(-220°)=-tan220°=-tan40°
sin520°=sin(360°+160°)=sin160°=sin(180°-20°)=sin20°
sin(-520°)=-sin520°=-sin20°
cos520°=cos(360°+160°)=cos160°=cos(180°-20°)=-cos20°
cos(-520°)=cos520°=-cos20°
tan520°=tan(180°*3-20°)=tan(-20°)=-tan20°
tan(-520°)=-tan520°=tan20°
完毕.
1年前
6