Question

срочно помоги минут 15 есть​

Answer 1

$frac{Cosalpha}{1-Sinalpha}=frac{Cosalpha(1+Sinalpha)}{(1-Sinalpha)(1+Sinalpha)}=frac{Cosalpha(1+Sinalpha)}{1-Sin^2alpha}=frac{Cosalpha(1+Sinalpha)}{Cos^2alpha}=frac{1+Sinalpha}{Cosalpha}$