\[ y'(x) (-\sin (y(x))+x \sin (x y(x))+\cos (y(x)+x))+y(x) \sin (x y(x))+\cos (y(x)+x)+\cos (x)=0 \] ✓ Mathematica : cpu = 0.850341 (sec), leaf count = 31
\[\text {Solve}[\cos (y(x))-\cos (x y(x))+\sin (x) \cos (y(x))+\cos (x) \sin (y(x))+\sin (x)=c_1,y(x)]\] ✓ Maple : cpu = 0.234 (sec), leaf count = 22
\[-\cos \left (x y \relax (x )\right )+\sin \relax (x )+\sin \left (y \relax (x )+x \right )+\cos \left (y \relax (x )\right )+c_{1} = 0\]