\[ y''(x)=2 y(x) \csc ^2(x) \] ✓ Mathematica : cpu = 0.0957729 (sec), leaf count = 64
\[\left \{\left \{y(x)\to \frac {c_1 \cos (x)}{\sqrt {\cos ^2(x)-1}}+\frac {c_2 \left (\cos (x) \log \left (\sqrt {\cos ^2(x)-1}+\cos (x)\right )-\sqrt {\cos ^2(x)-1}\right )}{\sqrt {\cos ^2(x)-1}}\right \}\right \}\]
✓ Maple : cpu = 0.299 (sec), leaf count = 57
\[ \left \{ y \left ( x \right ) ={\frac {{\it \_C1}\,\sin \left ( 2\,x \right ) }{\cos \left ( 2\,x \right ) -1}}+{\frac {{\it \_C2}\, \left ( -i\ln \left ( \cos \left ( 2\,x \right ) +i\sin \left ( 2\,x \right ) \right ) \sin \left ( 2\,x \right ) +2\,\cos \left ( 2\,x \right ) -2 \right ) }{\cos \left ( 2\,x \right ) -1}} \right \} \]