Question

упростить выражение. ​

Answer 1

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