\[ y^{(3)}(x) \sin (x)+(2 \cos (x)+1) y''(x)-\sin (x) y'(x)-\cos (x)=0 \] ✓ Mathematica : cpu = 0.996563 (sec), leaf count = 72
\[\left \{\left \{y(x)\to \frac {\sin \left (\frac {x}{2}\right ) \left (-2 \cos \left (\frac {x}{2}\right ) \sin ^{-1}(\cos (x))+\sqrt {2} \left (c_2 x \sin \left (\frac {x}{2}\right )+\cos \left (\frac {x}{2}\right ) (c_2 \log (2 (\cos (x)+1))+2 c_1)\right )\right )}{\cos (x)-1}+c_3\right \}\right \}\] ✓ Maple : cpu = 0.227 (sec), leaf count = 71
\[\left \{y \left (x \right ) = \frac {c_{1} \ln \left (\frac {-\cos \left (x \right )+1}{\sin \left (x \right )}\right ) \left (\sin ^{2}\left (x \right )\right )-c_{1} \ln \left (\sin \left (x \right )\right ) \left (\sin ^{2}\left (x \right )\right )+c_{3} \left (\sin ^{2}\left (x \right )\right )-x \left (\cos ^{2}\left (x \right )\right )+x +\left (\cos \left (x \right )-1\right ) \left (c_{1} x +c_{2}+1\right ) \sin \left (x \right )}{\left (\cos \left (x \right )-1\right ) \sin \left (x \right )}\right \}\]