Question

(1-ctga)/(1+ctga)= спростити вираз

Answer 1

$..=\frac{1 - \frac{\cos \alpha}{\sin \alpha}}{1+ \frac{\cos \alpha}{\sin \alpha}}= \frac{\sin \alpha - \cos \alpha}{\sin \alpha + \cos \alpha}$

Answer 2

Решение на фотографии.