\[ y'(x)=\frac {\sin \left (\frac {y(x)}{x}\right ) \csc \left (\frac {y(x)}{2 x}\right ) \sec \left (\frac {y(x)}{2 x}\right ) \left (2 x^3 \sin \left (\frac {y(x)}{2 x}\right ) \cos \left (\frac {y(x)}{2 x}\right )+y(x)\right )}{2 x} \] ✓ Mathematica : cpu = 0.109158 (sec), leaf count = 23
\[\left \{\left \{y(x)\to 2 x \cot ^{-1}\left (e^{-\frac {x^2}{2}-c_1}\right )\right \}\right \}\] ✓ Maple : cpu = 0.091 (sec), leaf count = 64
\[y \relax (x ) = \arctan \left (\frac {2 \,{\mathrm e}^{\frac {x^{2}}{2}} c_{1}}{{\mathrm e}^{x^{2}} c_{1}^{2}+1}, \frac {-{\mathrm e}^{x^{2}} c_{1}^{2}+1}{{\mathrm e}^{x^{2}} c_{1}^{2}+1}\right ) x\]