4sin^2 3x cos^2 3x + 8sin^2 3x=0
4sin^2x(cos^2 3x+2)=0
4sin^2 3x=0
sin^2 3x=0
1-cos6x/2=0
cos6x=1
6x=2pn
x=pn/3
sin^2 2x+cos4x=0
sin^2x+cos^2 2x-sin^2 2x=0
cos^2 2x=0
1+cos4x/2=0
cos4x=-1
4x=p+2pk
x=p/4+pk/2
4sin^2 3x cos^2 3x + 8sin^2 3x=0
4sin^2x(cos^2 3x+2)=0
4sin^2 3x=0
sin^2 3x=0
1-cos6x/2=0
cos6x=1
6x=2pn
x=pn/3
sin^2 2x+cos4x=0
sin^2x+cos^2 2x-sin^2 2x=0
cos^2 2x=0
1+cos4x/2=0
cos4x=-1
4x=p+2pk
x=p/4+pk/2