\[ y'(x)=(y(x)+\cos (x))^2+\sin (x) \] ✓ Mathematica : cpu = 0.110306 (sec), leaf count = 18
\[\left \{\left \{y(x)\to -\cos (x)+\frac {1}{-x+c_1}\right \}\right \}\] ✓ Maple : cpu = 0.078 (sec), leaf count = 16
\[y \relax (x ) = -\cos \relax (x )+\frac {1}{-x +c_{1}}\]