\[ \boxed { {\frac {{\rm d}^{2}}{{\rm d}{x}^{2}}}y \left ( x \right ) =-2\,{\frac {x{\frac {\rm d}{{\rm d}x}}y \left ( x \right ) }{{x}^{2}+1}}-{\frac {y \left ( x \right ) }{ \left ( {x}^{2}+1 \right ) ^{2}}}=0} \]
Mathematica: cpu = 0.022503 (sec), leaf count = 31 \[ \left \{\left \{y(x)\to \frac {c_1}{\sqrt {x^2+1}}+\frac {c_2 x}{\sqrt {x^2+1}}\right \}\right \} \]
Maple: cpu = 0.016 (sec), leaf count = 24 \[ \left \{ y \left ( x \right ) ={x{\it \_C1}{\frac {1}{\sqrt {{x}^{2}+1}} }}+{{\it \_C2}{\frac {1}{\sqrt {{x}^{2}+1}}}} \right \} \]