[tex]\frac{2\cos\alpha+\sin\alpha}{\cos\alpha-3\sin\alpha}:\frac{\cos\alpha}{\cos\alpha}=\frac{2\frac{\cos\alpha}{\cos\alpha}+\frac{\sin\alpha}{\cos\alpha}}{\frac{\cos\alpha}{\cos\alpha}-3\frac{\sin\alpha}{\cos\alpha}}=\frac{2+\text{tg }\alpha}{1-3\text{tg }}=\frac{2+2}{1-3*2}=\frac{4}{-5}=-\frac{4}{5}[/tex]
