\[ y'(x)+y(x) \cos (x)-e^{2 x}=0 \] ✓ Mathematica : cpu = 3.18143 (sec), leaf count = 38
\[\left \{\left \{y(x)\to e^{-\sin (x)} \int _1^x e^{2 K[1]+\sin (K[1])} \, dK[1]+c_1 e^{-\sin (x)}\right \}\right \}\]
✓ Maple : cpu = 0.076 (sec), leaf count = 27
\[ \left \{ y \left ( x \right ) ={{\rm e}^{-\sin \left ( x \right ) }}\int \!{{\rm e}^{2\,x+\sin \left ( x \right ) }}\,{\rm d}x+{{\rm e}^{-\sin \left ( x \right ) }}{\it \_C1} \right \} \]