\[ y'(x)=\frac {x^4 \left (-\sqrt {x^2+y(x)^2}\right )+x^3 y(x) \sqrt {x^2+y(x)^2}+y(x)}{x} \] ✓ Mathematica : cpu = 0.140372 (sec), leaf count = 87
\[\left \{\left \{y(x)\to \frac {x \left (-2 e^{\frac {4 c_1+x^4}{2 \sqrt {2}}}+e^{\frac {4 c_1+x^4}{\sqrt {2}}}-1\right )}{2 e^{\frac {4 c_1+x^4}{2 \sqrt {2}}}+e^{\frac {4 c_1+x^4}{\sqrt {2}}}-1}\right \}\right \}\]
✓ Maple : cpu = 0.183 (sec), leaf count = 49
\[ \left \{ \ln \left ( 2\,{\frac {x \left ( \sqrt {2\, \left ( y \left ( x \right ) \right ) ^{2}+2\,{x}^{2}}+y \left ( x \right ) +x \right ) }{y \left ( x \right ) -x}} \right ) +{\frac {\sqrt {2}{x}^{4}}{4}}-\ln \left ( x \right ) -{\it \_C1}=0 \right \} \]