sin（-10π/3）
=sin(-4π+2π/3)
=sin(2π/3)
=sin(π-π/3)
=sin(π/3)
=√3/2为什么sin（-10π/3）=sin(-4π+2π/3)为什么成了(-4π+2π/3)因为 -10/3= -4 + 2/3 所以 -10π/3=-4π+2π/3