\[ y'(x)+y(x) \cos (x)-\frac {1}{2} \sin (2 x)=0 \] ✓ Mathematica : cpu = 0.0231265 (sec), leaf count = 18
\[\left \{\left \{y(x)\to c_1 e^{-\sin (x)}+\sin (x)-1\right \}\right \}\]
✓ Maple : cpu = 0.021 (sec), leaf count = 15
\[ \left \{ y \left ( x \right ) =\sin \left ( x \right ) -1+{{\rm e}^{-\sin \left ( x \right ) }}{\it \_C1} \right \} \]