\[\left[ {{\text{Ламберт}}} \right]\] $$\operatorname{tg} x = \cfrac{x}{{1 - \cfrac{{{x^2}}}{{3 - \cfrac{{{x^2}}}{{5 - \cfrac{{{x^2}}}{{7 - ...}}}}}}}} = \cfrac{1}{{\cfrac{1}{x} - \cfrac{1}{{\cfrac{3}{x} - \cfrac{1}{{\cfrac{5}{x} - \cfrac{1}{{\cfrac{7}{x} - \cfrac{1}{{...}}}}}}}}}}$$