\[ \boxed { {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) =1/2\,{\frac {-2\,\cos \left ( y \left ( x \right ) \right ) +{x}^{3}\cos \left ( 2\,y \left ( x \right ) \right ) \ln \left ( x \right ) +{x}^{3}\ln \left ( x \right ) }{\sin \left ( y \left ( x \right ) \right ) \ln \left ( x \right ) x}}=0} \]
Mathematica: cpu = 0.384049 (sec), leaf count = 63 \[ \left \{\left \{y(x)\to -\sec ^{-1}\left (\frac {-9 c_1-x^3+3 x^3 \log (x)}{9 \log (x)}\right )\right \},\left \{y(x)\to \sec ^{-1}\left (\frac {-9 c_1-x^3+3 x^3 \log (x)}{9 \log (x)}\right )\right \}\right \} \]
Maple: cpu = 0.500 (sec), leaf count = 27 \[ \left \{ y \left ( x \right ) =\arccos \left ( 9\,{\frac {\ln \left ( x \right ) }{3\,{x}^{3}\ln \left ( x \right ) -{x}^{3}+9\,{\it \_C1}}} \right ) \right \} \]