X=-3COS(4π/3)=-3*(-1/2)=3/2Y=-3SIN(4π/3)=-3*(-√3/2)=3√3/2极坐标一点(-3,4π/3)的直角坐标是3/2,3√3/2 同理若是极坐标一点(-3,-4π/3)X=-3COS(-4π/3)=-3COS(2π/3)=-3*(-1/2)=3/2Y=-3SIN(-4π/3)=-3*SIN(2...