sin^2 3x+3 cos^2 3x-4 sin (П/2+3х) cos(П/2+3х)=0
sin^2 3x+3(1- sin^2 3x) -2 *2sin2(П/2+3х)=0
sin^2 3x+3-3sin^2 3x - 4cos2x = 0
-2sin^2 3x - 4( cos^2 x-sin^2 x)= 0
-2sin^2 3x -4cos^2 x + 4sin^2x=0
2sin^2 x -4(1-sin^2x)=0
2sin^2 x - 4 +4sin^2 x=0
6 sin^2 x=4
sin^2x=4/6
sin^2 x=2/3
sinx=2/3 sinx=-2/3
x=(-1)^n arcsin(2/3)+Пn x=(-1)^n arcsin(-2/3)+Пn
x=(-1)^n -arcsin(2/3)+Пn
x=(-1)^n+1 arcsin(2/3)+Пn
