\[ \boxed { \left ( \left ( y \left ( x \right ) \right ) ^{2}+4\,\sin \left ( x \right ) \right ) {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) -\cos \left ( x \right ) =0} \]
Mathematica: cpu = 0.064508 (sec), leaf count = 39 \[ \text {Solve}\left [-\frac {1}{32} e^{-4 y(x)} \left (8 y(x)^2+4 y(x)+1\right )-e^{-4 y(x)} \sin (x)=c_1,y(x)\right ] \]
Maple: cpu = 0.047 (sec), leaf count = 33 \[ \left \{ -{{\rm e}^{-4\,y \left ( x \right ) }}\sin \left ( x \right ) -{ \frac { \left ( 8\, \left ( y \left ( x \right ) \right ) ^{2}+4\,y \left ( x \right ) +1 \right ) {{\rm e}^{-4\,y \left ( x \right ) }}}{32}} +{\it \_C1}=0 \right \} \]