Question

Упростите выражения :
sina/1-cosa - 1+cosa/sina

Answer 1

$\frac{Sin\alpha}{1-Cos\alpha}-\frac{1+Cos\alpha}{Sin\alpha}=\frac{Sin\alpha*Sin\alpha-(1-Cos\alpha)(1+Cos\alpha)}{Sin\alpha(1-Cos\alpha)}=\frac{Sin^{2}\alpha-1+Cos^{2}\alpha}{Sin\alpha(1-Cos\alpha)}=\frac{1-1}{Sin\alpha(1-Cos\alpha)}=\\=\frac{0}{Sin\alpha(1-Cos\alpha)}=0\\\\Otvet:\boxed{0}$