\[ y''(x)=\cot (2 x) y'(x)-2 y(x) \] ✓ Mathematica : cpu = 0.200745 (sec), leaf count = 64
\[\left \{\left \{y(x)\to -\frac {2}{3} c_2 \cos (2 x) \cos ^{\frac {3}{2}}(x) \, _2F_1\left (\frac {1}{4},\frac {3}{4};\frac {7}{4};\cos ^2(x)\right )+\frac {1}{2} c_1 \cos (2 x)-2 c_2 \sin ^2(x)^{3/4} \cos ^{\frac {3}{2}}(x)\right \}\right \}\]
✓ Maple : cpu = 0.233 (sec), leaf count = 30
\[ \left \{ y \left ( x \right ) = \left ( \sin \left ( 2\,x \right ) \right ) ^{{\frac {3}{4}}} \left ( {\it LegendreQ} \left ( {\frac {1}{4}},{\frac {3}{4}},\cos \left ( 2\,x \right ) \right ) {\it \_C2}+{\it LegendreP} \left ( {\frac {1}{4}},{\frac {3}{4}},\cos \left ( 2\,x \right ) \right ) {\it \_C1} \right ) \right \} \]