Question

Пж помогите
sin² α /cos α-cos² α

Answer 1

$\displaystyle\frac{\sin^2\alpha}{\cos\alpha-\cos^2\alpha} = \frac{1-\cos^2\alpha}{\cos\alpha(1-\cos\alpha)} = \frac{(1-\cos\alpha)(1+\cos\alpha)}{\cos\alpha(1-\cos\alpha)} =\\\\=\frac{1+\cos\alpha}{\cos\alpha} = 1+\frac{1}{\cos\alpha} = 1+\sec\alpha$