Решите номер 39.Есть вложение.

Решите задачу:

$1- \cfrac{1}{1- \cfrac{a}{1- \frac{1}{a+1} } } =1- \cfrac{1}{1- \cfrac{a}{ \frac{a+1-1}{a+1} } } = 1- \cfrac{1}{1- \cfrac{a}{ \frac{a}{a+1} } } =1- \frac{1}{1- a-1} } } = \\\ =1- \frac{1}{- a} } } = \frac{a+1}{ a} } }$

$1+ \cfrac{x}{1- \cfrac{x}{x+ \frac{x}{x-1} } } =1+\cfrac{x}{1- \cfrac{x}{ \frac{x^2-x+x}{x-1} } } = 1+ \cfrac{x}{1- \cfrac{x}{ \frac{x^2}{x-1} } } =1+ \cfrac{x}{1- \frac{x-1}{x } } = \\\ =1+ \cfrac{x}{ \frac{x-x+1}{x } } =1+ \cfrac{x}{ \frac{1}{x } } =1+x^2$