6x-12=плюс минус arccos(4/7)+2pi*n 6x=12+-arccos(4/7)+2pi*n x=2+-(1/6)arccos(4/7)+pi*n/3
2x/pi=pi/2+pi*n 2x=(pi)^2/2+(pi)^2n x=(pi)^2/4+(pi)^2n/2
6x-12=плюс минус arccos(4/7)+2pi*n
6x=12+-arccos(4/7)+2pi*n
x=2+-(1/6)arccos(4/7)+pi*n/3
2x/pi=pi/2+pi*n
2x=(pi)^2/2+(pi)^2n
x=(pi)^2/4+(pi)^2n/2