求下列各三角函数值sin18π,cos25π,sin13π/3,cos103π/4,tan17π/4

sin(18π)=0
cos(25π)=－1
sin(13π/3)=√3/2
cos(103π/4)=－√2/2
tan(17π/4)=1详细过程sin(18π)=sin(9×2π＋0)=sin0=0cos(25π)=cos(12×2π＋π)=cosπ=－1sin(13π/3)=sin[4π＋(π/3)]=sin(π/3)=√3/2cos(103√/4)=cos[25π＋(3π/4)]=cos(3π/4)=cos[π－π/4]=－cos(π/4)=－√2/2tan(17π/4)=tan(4π＋π/4)=tan(π/4)=1