x/2 заменяем на t
1-cos2t-2sint=0
1-(1-2sin^2t)-2sint=0
1-1+2sn^2t-2sint=0
sin^2t-sint=0
sint(sint-1)=0
sint=0 sint=1
t=(pi)*k t=(pi)/2+2(pi)*n
x=2(pi)*k x=(pi)+4(pi)*n
