\[ y'(x) \left (y(x)^2+4 \sin (x)\right )-\cos (x)=0 \] ✓ Mathematica : cpu = 0.0760527 (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 = 0.057 (sec), leaf count = 33
\[ \left \{ -{{\rm e}^{-4\,y \left ( x \right ) }}\sin \left ( x \right ) -{\frac { \left ( 8\, \left ( y \left ( x \right ) \right ) ^{2}+4\,y \left ( x \right ) +1 \right ) {{\rm e}^{-4\,y \left ( x \right ) }}}{32}}+{\it \_C1}=0 \right \} \]