\[\boxed{\mathbf{920\ (920).\ }Еуроки\ - \ ДЗ\ без\ мороки}\]
\[y =\]
\[= \underset{\begin{matrix} бесконечная\ геометрическая\ \\ прогрессия \\ \end{matrix}}{\overset{x^{2} + \frac{x^{2}}{1 + x^{2}} + \frac{x^{2}}{\left( 1 + x^{2} \right)^{2}} + \ldots}{︸}},\ \]
\[\ x \neq 0\]
\[q = \frac{x^{2}}{1 + x^{2}}\ \ :x^{2} = \frac{1}{1 + x^{2}}\]
\[S = \frac{x^{2}}{1 - \frac{1}{1 + x^{2}}} = \frac{x^{2}}{\frac{1 + x^{2} - 1}{1 + x^{2}}} =\]
\[= \frac{x^{2}\left( 1 + x^{2} \right)}{x^{2}} = 1 + x^{2};\ \ x \neq 0\]
\[y = x^{2} + 1;\ \ x \neq 0\ \]
\[график\ y = x^{2}\ перенести\ на\ \]
\[1\ единицу\ вверх.\]