\[ y^{(3)}(x) \sin (x)+(2 \cos (x)+1) y''(x)-\sin (x) y'(x)-\cos (x)=0 \] ✓ Mathematica : cpu = 0.667355 (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 = 0.348 (sec), leaf count = 71
\[ \left \{ y \left ( x \right ) ={\frac {1}{\sin \left ( x \right ) \left ( \cos \left ( x \right ) -1 \right ) } \left ( \left ( \sin \left ( x \right ) \right ) ^{2}\ln \left ( {\frac {1-\cos \left ( x \right ) }{\sin \left ( x \right ) }} \right ) {\it \_C1}-\ln \left ( \sin \left ( x \right ) \right ) \left ( \sin \left ( x \right ) \right ) ^{2}{\it \_C1}+ \left ( \sin \left ( x \right ) \right ) ^{2}{\it \_C3}+ \left ( \cos \left ( x \right ) -1 \right ) \left ( {\it \_C1}\,x+{\it \_C2}+1 \right ) \sin \left ( x \right ) - \left ( \cos \left ( x \right ) \right ) ^{2}x+x \right ) } \right \} \]