\[ y^{(3)}(x) \sin (x)+(2 \cos (x)+1) y''(x)-\sin (x) y'(x)-\cos (x)=0 \] ✓ Mathematica : cpu = 0.617873 (sec), leaf count = 72
\[\left \{\left \{y(x)\to \frac {\sin \left (\frac {x}{2}\right ) \left (\sqrt {2} \left (c_2 x \sin \left (\frac {x}{2}\right )+\cos \left (\frac {x}{2}\right ) \left (c_2 \log (2 (\cos (x)+1))+2 c_1\right )\right )-2 \cos \left (\frac {x}{2}\right ) \sin ^{-1}(\cos (x))\right )}{\cos (x)-1}+c_3\right \}\right \}\]
✓ Maple : cpu = 0.236 (sec), leaf count = 69
\[ \left \{ y \left ( x \right ) ={\frac {{\it \_C1}}{\cos \left ( x \right ) -1} \left ( \cos \left ( x \right ) x-\ln \left ( \sin \left ( x \right ) \right ) \sin \left ( x \right ) +\ln \left ( -{\frac {\cos \left ( x \right ) -1}{\sin \left ( x \right ) }} \right ) \sin \left ( x \right ) -x \right ) }+{\it \_C2}+{\frac {\sin \left ( x \right ) {\it \_C3}}{\cos \left ( x \right ) -1}}-{\frac {\cos \left ( x \right ) x-\sin \left ( x \right ) +x}{\sin \left ( x \right ) }} \right \} \]