Sin2x+cos4x=
sin2x+1-2sin^2x=0 1-2sin^2×2x+sin2x=0 -sin2x+2sin^2×2x-1=0 sin2x=t 2t^2-t-1=0 D=(-1)^2-4×2(-1)=9 x1,2=1+_3/4 x1=1 x2=-1/2 sinx=1 x=n/2+2Пп sinx=-1/2 x=n/6-2Пm x2=5n/6-2nk