Question

cos^2l-cos^4l+sin^4l упростить

Answer 1

$cos^2 alpha -cos^4 alpha +sin^4 alpha =cos^2 alpha (1-cos^2 alpha )+sin^4 alpha =\\=cos^2 alpha cdot sin^2 alpha +sin^4 alpha =sin^2 alpha (cos^2 alpha +sin^2 alpha )=sin^2 alpha cdot 1=sin^2 alpha$