\[ y'(x)=\frac {x}{\sqrt {x^2+1}+y(x)} \] ✓ Mathematica : cpu = 0.244762 (sec), leaf count = 88
\[\text {Solve}\left [\frac {1}{2} \left (\log \left (-\frac {y(x)^2}{x^2+1}-\frac {y(x)}{\sqrt {x^2+1}}+1\right )+\log \left (x^2+1\right )\right )=\frac {\tanh ^{-1}\left (\frac {3 \sqrt {x^2+1}+y(x)}{\sqrt {5} \left (\sqrt {x^2+1}+y(x)\right )}\right )}{\sqrt {5}}+c_1,y(x)\right ]\] ✓ Maple : cpu = 0.437 (sec), leaf count = 115
\[\left \{-c_{1}-\frac {4 \sqrt {5}\, \arctanh \left (\frac {\left (y \left (x \right )+3 \sqrt {x^{2}+1}\right ) \sqrt {5}}{5 y \left (x \right )+5 \sqrt {x^{2}+1}}\right )}{15}-\frac {4 \ln \left (\frac {36 \sqrt {x^{2}+1}}{y \left (x \right )+\sqrt {x^{2}+1}}\right )}{3}+\frac {2 \ln \left (-\frac {1296 \left (-x^{2}+y \left (x \right )^{2}+\sqrt {x^{2}+1}\, y \left (x \right )-1\right )}{11 \left (y \left (x \right )+\sqrt {x^{2}+1}\right )^{2}}\right )}{3}+\frac {2 \ln \left (x^{2}+1\right )}{3} = 0\right \}\]