Sin ^4 12x - cos ^4 12x = cos 8x

Question

Sin ^4 12x - cos ^4 12x = cos 8x

Answer 1

Sin ^ 4 12x - cos ^ 4 12x=
=(sin^2 12x-cos^2 12x)(sin^2 12x+
cos^2 12x)=
=-(cos^2 12x - sin^2 12x)= -cos24x