sin^4x+cos^4x+1/2sin^2*2x=sin^4x+cos^4x+1/2(2sinxcosx)^2=sin^4x+cos^4x+2sin^2xcos^2x=
=(sin^2x+cos^2x)^2=1^2=1
sin^4x+cos^4x+1/2sin^2*2x=sin^4x+cos^4x+1/2(2sinxcosx)^2=sin^4x+cos^4x+2sin^2xcos^2x=
=(sin^2x+cos^2x)^2=1^2=1