Question

1-cosa+cos2a/sin2a-sina решите пожалуйста срочно​

Answer 1

$\frac{1-Cos\alpha+Cos2\alpha}{Sin2\alpha-Sin\alpha}=\frac{(1+Cos2\alpha)-Cos\alpha}{2Sin\alpha Cos\alpha-Sin\alpha}=\frac{2Cos^{2}\alpha-Cos\alpha}{Sin\alpha(2Cos\alpha-1)}=\frac{Cos\alpha(2Cos\alpha-1)}{Sin\alpha(2Cos\alpha-1)}=\frac{Cos\alpha}{Sin\alpha}=Ctg\alpha\\\\Otvet:\boxed{Ctg\alpha}$