高中数学：求下列各角的正弦、余弦、正切值

Question

750° 、17π/4、-11π/6、-1020°

Answer 1

sin750°=sin(720°+30°)=sin30°=1/2
cos750°=cos(720°+30°)=cos30°=根号3/2
tan750°=tan(720°+30°)=tan30°=根号3/3
sin17π/4=sin(16π/4+π/4)=sin(π/4)=根号2/2
cos17π/4=cos(16π/4+π/4)=cos(π/4)=根号2/2
tan17π/4=tan(16π/4+π/4)=tan(π/4)=1
sin(-11π/6)=sin(-12π/6+π/6)=sin(π/6)=1/2
cos(-11π/6)=cos(-12π/6+π/6)=cos(π/6)=根号3/2
tan(-11π/6)=tan(-12π/6+π/6)=tan(π/6)=根号3/3
sin(-1020°)=sin(-1080°+60°)=sin60°=根号3/2
cos(-1020°)=cos(-1080°+60°)=cos60°=1/2
tan(-1020°)=tan(-1080°+60°)=tan60°=根号3

Answer 2

1.
sin750°=sin(2*360°+30°)=sin30°=1/2
cos750°=cos30°=√3/2
tan750°=tan30°=√3/3
2.
sin17π/4=sin(4π+π/4)=sinπ/4=√2/2
cos17π/4=cosπ/4=√2/2
tan17π/4=tanπ/4=1
3.
sin-11π/6=sin(-2π+π/6)=sinπ/6=1/2
cos-11π/6=cosπ/6=√3/2
tan-11π/6=tanπ/6=√3/3
4.
sin-1020°=sin(-1020°+3*360°)=sin60°=√3/2
cos-1020°=cos60°=1/2
tan-1020°=tan60°=√3