sin^2x=(1-cos(2x))/2sin2x=1−cos(2x)2
cos^2x=(1+cos(2x))/2cos2x=1+cos(2x)2
sin^2xcos^2x=((1+cos(2x))(1-cos(2x)))/4=(1-cos^2(2x))/4sin2xcos2x=(1+cos(2x))(1−cos(2x))4=1−cos2(2x)4
cos^2(2x)=(1+cos(4x))/2cos2(2x)=1+cos(4x)2
(1-(1+cos(4x))/2)/4=(2-(1+cos(4x)))/8=(1-cos(4x))/81−1+cos(4x)24=2−(1+cos(4x))8=1−cos(4x)8