\[ y''(x)=2 y(x) \csc ^2(x) \] ✓ Mathematica : cpu = 0.076626 (sec), leaf count = 58
\[\left \{\left \{y(x)\to \frac {c_1 \cos (x)}{\sqrt {\cos ^2(x)-1}}+\frac {c_2 \left (\cos (x) \left (-\sin ^{-1}(\cos (x))\right )-\sqrt {1-\cos ^2(x)}\right )}{\sqrt {1-\cos ^2(x)}}\right \}\right \}\] ✓ Maple : cpu = 0.705 (sec), leaf count = 50
\[ \left \{ y \left ( x \right ) ={\frac {-i\sin \left ( 2\,x \right ) \ln \left ( \cos \left ( 2\,x \right ) +i\sin \left ( 2\,x \right ) \right ) {\it \_C2}+{\it \_C1}\,\sin \left ( 2\,x \right ) +2\,{\it \_C2}\, \left ( \cos \left ( 2\,x \right ) -1 \right ) }{\cos \left ( 2\,x \right ) -1}} \right \} \]