Sin3x+П/4 =(Меньше или равно)= -корень(2)/2
sin(3x+П/4)≤√2/2
-π-arcsina
-π-π/4+2πn<3x+П/4<π/4+2πn, n∈z</p>
-2π/2-π/2+2πn<3x<2πn, n∈z</p>
-3π/2+2πn<3x<2πn, n∈z</p>
-π/2+2πn/3