\[\boxed{\text{19\ (19).}\text{\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
Пояснение.
Решение.
\[y = x^{2}:\ \ \]
\[D(y) = R;\ \ \]
\[E(y) = \lbrack 0;\ + \infty).\]
\[y = x^{3}:\ \]
\[D(y) = R;\ \ \ \]
\[E(y) = R.\]
\[y = \sqrt{x}:\]
\[D(y) = \lbrack 0; + \infty);\ \ \ \]
\[E(y) = \lbrack 0; + \infty).\]