\[ y'(x)=\frac {\frac {1}{2} x^4 \cos (2 y(x))+\frac {x^4}{2}-\frac {1}{2} x \sin (2 y(x))-\frac {1}{2} \sin (2 y(x))}{x (x+1)} \] ✓ Mathematica : cpu = 0.605085 (sec), leaf count = 43
\[\left \{\left \{y(x)\to \tan ^{-1}\left (\frac {3 x^4-4 x^3+6 x^2-12 x+12 \log (x+1)-25-12 c_1}{12 x}\right )\right \}\right \}\] ✓ Maple : cpu = 1.323 (sec), leaf count = 38
\[y \relax (x ) = \arctan \left (\frac {3 x^{4}-4 x^{3}+6 x^{2}+12 \ln \left (1+x \right )-12 c_{1}-12 x}{12 x}\right )\]