4pi/3sinx=pi/6+2pik
sinx=3/4(1/6+2k)=1/8+3/2k<1 k<7/12
sinx=1/8+3/2k>-1 k>-3/4
k=0
sinx=1/8
x=arcsin(1/8)
sinx=3/4(5/6+2k)=5/8+3/2k<1 k<1/4
5/8+3/2k>-1
k=0 sinx=5/8
x=arcsin(5/8)
k=-1 sinx=5/8-3/2=-7/8
x=arcsin(-7/8)
4pi/3sinx=pi/6+2pik
sinx=3/4(1/6+2k)=1/8+3/2k<1 k<7/12
sinx=1/8+3/2k>-1 k>-3/4
k=0
sinx=1/8
x=arcsin(1/8)
sinx=3/4(5/6+2k)=5/8+3/2k<1 k<1/4
5/8+3/2k>-1
k=0 sinx=5/8
x=arcsin(5/8)
k=-1 sinx=5/8-3/2=-7/8
x=arcsin(-7/8)