sin2x-cos2x=(корень из 2)sin2x
sqrt(2)/2*sin2x-sqrt(2)/2*cos2x=sqrt(2)*sqrt(2)/2*sin2x
sin(2x-П/4)=sin2x
sin2x=sqrt(1/2(1-cos4x))
sin(2x-П/4)=sqrt(1/2(1-cos(4x-П/2))
cos4x=cos(4x-П/2)=sin4x
tg4x=1
4x=П/4+Пn
x=П/16+Пn/4