1.α=-17π/3
sin(-17π/3)=-sin(17π/3)=-sin(3*2π-π/3)=-(-sinπ/3=sinππ/3=√3/2；
cos(-17π/3)=cos17π/3)=cos(2*3π-π/3)=cosπ/3=1/3；
tan(-17π/3)=-tan(17π/3)=-tan(2*3π-π/3)=-(-tanπ/3)=tanπ/3=√3.
2,α=-23π/6.
sin(-23π/6)=-sin(23π/6)=-sin(4π-π/6)=sinπ/6=1/2.
cos(-23π/6)=cos23π/6)=cos(4π-π/6)=cosπ/6=√3/2.
tan(-23π/6)=-tan(23π/6）＝yanπ/6=√3/3.
3.1500°
sin1500°=sin(4*360°+60°)=sin60°＝√3/2；
cos(1500°)=cos(4*360°+60°)=cos60°=1/2；
tan（1500°)=tan(4*360°+60°)=tan60°=√3.