\[ y''(x)=-\csc (x) y'(x) \left (\sin ^2(x)-\cos (x)\right )-y(x) \sin ^2(x) \] ✓ Mathematica : cpu = 0.161005 (sec), leaf count = 52
\[\left \{\left \{y(x)\to c_1 e^{\frac {\cos (x)}{2}} \cos \left (\frac {1}{2} \sqrt {3} \cos (x)\right )+c_2 e^{\frac {\cos (x)}{2}} \sin \left (\frac {1}{2} \sqrt {3} \cos (x)\right )\right \}\right \}\]
✓ Maple : cpu = 0.151 (sec), leaf count = 35
\[ \left \{ y \left ( x \right ) ={\it \_C1}\,{{\rm e}^{{\frac {\cos \left ( x \right ) }{2}}}}\sin \left ( {\frac {\sqrt {3}\cos \left ( x \right ) }{2}} \right ) +{\it \_C2}\,{{\rm e}^{{\frac {\cos \left ( x \right ) }{2}}}}\cos \left ( {\frac {\sqrt {3}\cos \left ( x \right ) }{2}} \right ) \right \} \]