( 1 - 8 sin x/3 cos 2/3 ) =0

(1-8sin x/3 cos x/3)=0-4*2sin x/3 cos x/3=-1sin(2x/3)=1/42x/3=(-1)^n arcsin(1/4) +πn, n-celoex=(-1)^n *(3/2arcsin1/4) +3/2 *πn