\[ 3 \sin (x) y'(x) \sin (y(x))+5 y(x) \cos ^4(x)=0 \] ✓ Mathematica : cpu = 0.061548 (sec), leaf count = 45
\[\left \{\left \{y(x)\to \text {SinIntegral}^{(-1)}\left (c_1-\frac {5}{3} \left (\frac {5 \cos (x)}{4}+\frac {1}{12} \cos (3 x)+\log \left (\sin \left (\frac {x}{2}\right )\right )-\log \left (\cos \left (\frac {x}{2}\right )\right )\right )\right )\right \}\right \}\] ✓ Maple : cpu = 0.311 (sec), leaf count = 28
\[ \left \{ {\frac {\cos \left ( 3\,x \right ) }{12}}+{\frac {5\,\cos \left ( x \right ) }{4}}+\ln \left ( \csc \left ( x \right ) -\cot \left ( x \right ) \right ) +{\frac {3\,{\it Si} \left ( y \left ( x \right ) \right ) }{5}}+{\it \_C1}=0 \right \} \]