Question

cos^2 x - cos x sin x =0

Answer 1

$cos^2 x - cos x sin x =0\cosx(cosx-sinx)=0\\cosx=0\x=frac{pi}{2}+pi n, ; nin Z;\\cosx-sinx=0|:(-cosx), ; cosx neq 0, ; x neq frac{pi}{2}+pi n, ; nin Z\tgx-1=0\tgx=1\x=frac{pi}{4}+pi n, ; nin Z.$