\[\boxed{\text{1083.\ }\text{еуроки}\text{-}\text{ответы}\text{\ }\text{на}\text{\ }\text{пятёрку}}\]
\[y = \frac{x^{2}}{x^{2} + 1}:\]
\[x^{2} + 1 > 0 \Longrightarrow D(y) = R.\]
\[x² < x² + 1 \Longrightarrow E(y) = \lbrack 0;1).\]