\[\boxed{\mathbf{15}\mathbf{.}}\]
\[\textbf{а)}\ y = \sqrt{|x|};\ \ \lbrack - 1;1\rbrack\]
\[y^{'} = \frac{1}{2\sqrt{|x|}} \cdot \frac{x}{|x|} = \frac{x}{2\sqrt{|x|^{3}}};\]
\[\frac{x}{2\sqrt{|x|^{3}}} = 0\]
\[x \neq 0.\]
\[При\ x = 0\ производная\ f^{'}(x)\]
\[\ не\ существует.\]
\[0 \in \lbrack - 1;1\rbrack.\]
\[y(0) = 0;\]
\[y( - 1) = 1;\]
\[y(1) = 1.\]
\[\max{f(x)} = 1;\]
\[\min{f(x)} = 0.\]
\[\textbf{б)}\ y = \sqrt{|x|};\ \ ( - 1;1)\]
\[y^{'} = \frac{1}{2\sqrt{|x|}} \cdot \frac{x}{|x|} = \frac{x}{2\sqrt{|x|^{3}}};\]
\[\frac{x}{2\sqrt{|x|^{3}}} = 0\]
\[x \neq 0.\]
\[При\ x = 0\ производная\ f^{'}(x)\]
\[не\ существует.\]
\[0 \in ( - 1;1).\]
\[y(0) = 0.\]
\[\max{f(x)} = 1 = нет;\]
\[\min{f(x)} = 0.\]
\[\textbf{в)}\ y = \sqrt{|x|};\ \ \lbrack - 1;1)\]
\[y^{'} = \frac{1}{2\sqrt{|x|}} \cdot \frac{x}{|x|} = \frac{x}{2\sqrt{|x|^{3}}};\]
\[\frac{x}{2\sqrt{|x|^{3}}} = 0\]
\[x \neq 0.\]
\[При\ x = 0\ производная\ f^{'}(x)\]
\[\ не\ существует.\]
\[0 \in \lbrack - 1;1).\]
\[y(0) = 0;\]
\[y( - 1) = 1.\]
\[\max{f(x)} = 1;\]
\[\min{f(x)} = 0.\]
\[\textbf{г)}\ y = \sqrt{|x|};\ \ ( - 1;1\rbrack\]
\[y^{'} = \frac{1}{2\sqrt{|x|}} \cdot \frac{x}{|x|} = \frac{x}{2\sqrt{|x|^{3}}};\]
\[\frac{x}{2\sqrt{|x|^{3}}} = 0\]
\[x \neq 0.\]
\[При\ x = 0\ производная\ f^{'}(x)\ \]
\[не\ существует.\]
\[0 \in ( - 1;1\rbrack.\]
\[y(0) = 0;\]
\[y(1) = 1.\]
\[\max{f(x)} = 1;\]
\[\min{f(x)} = 0.\]