sinx-√3cosx
=2[(1/2)sinx-((√3)/2)cosx]
=2[cos(π/3)sinx-sin(π/3)cosx]
=2sin[x-(π/3)],
所以θ=2kπ-(π/3)（因为sinx的周期是2π),k为整数,因为θ属于(0,2π),
所以k=1,θ=5π/3.