\[\boxed{\text{5.4}\text{3}\text{1.}}\]
\[Возьмем\ дробь\ \frac{3}{7}.\]
\[\frac{3}{7};\ \frac{1}{3};\ \frac{4}{1};\ \frac{5}{4};\ \frac{9}{5};\ \frac{5}{9};\ \frac{5}{5};\ \frac{1}{5};\ \frac{6}{1};\ \frac{7}{6};\]
\[\ \frac{4}{7};\ \frac{2}{4};\ \frac{6}{2};\ \frac{8}{6};\ \frac{5}{8};\ \frac{4}{5};\ \frac{9}{4};\ \frac{4}{9};\ \frac{4}{4};\ \frac{8}{4};\]
\[\ \frac{3}{8};\frac{2}{3};\ \frac{5}{2};\ \frac{7}{5};\ \frac{3}{7};\ \frac{1}{3};\ \frac{4}{1};\ \frac{5}{4};\ \frac{9}{5};\ \frac{5}{9};\ \]
\[\frac{5}{5};\ \frac{1}{5};\ \frac{6}{1};\ \frac{7}{6};\ \frac{4}{7}\ldots\ \ \ \ \]