0度=0,30度=π/6,45度=π/4,60度=π/3,90度=π/2,120度=2π/3,135度=3π/4,150度=5π/6,180度=π,210度=7π/6,225度=5π/4,240度=4π/3,270度=3π/2,300度=5π/3,315度=7π/4,330度=11π/6,360度=2π