\[ y''(x)+y(x)^3 y'(x)-y(x) y'(x) \sqrt {4 y'(x)+y(x)^4}=0 \] ✓ Mathematica : cpu = 0.186093 (sec), leaf count = 43
\[\left \{\left \{y(x)\to e^{c_1} \tan \left (e^{3 c_1} \left (c_2+x\right )\right )\right \},\left \{y(x)\to e^{c_1} \tanh \left (e^{3 c_1} \left (c_2+x\right )\right )\right \}\right \}\] ✓ Maple : cpu = 0.304 (sec), leaf count = 35
\[ \left \{ y \left ( x \right ) ={\frac {1}{{\it \_C1}}\tan \left ( {({\it \_C2}+x) \left ( {{\it \_C1}}^{2} \right ) ^{-{\frac {3}{2}}}} \right ) },y \left ( x \right ) ={\frac {1}{{\it \_C1}}\tanh \left ( {({\it \_C2}+x) \left ( {{\it \_C1}}^{2} \right ) ^{-{\frac {3}{2}}}} \right ) } \right \} \]