\[ x \left (y''(x)+y(x)\right )-\cos (x)=0 \] ✓ Mathematica : cpu = 0.0171449 (sec), leaf count = 41
\[\left \{\left \{y(x)\to \frac {1}{2} (\text {Ci}(2 x) \sin (x)-\text {Si}(2 x) \cos (x)+\log (x) \sin (x))+c_1 \cos (x)+c_2 \sin (x)\right \}\right \}\] ✓ Maple : cpu = 0.054 (sec), leaf count = 35
\[y \relax (x ) = \frac {\sin \relax (x ) \Ci \left (2 x \right )}{2}-\frac {\Si \left (2 x \right ) \cos \relax (x )}{2}+\frac {\left (2 c_{2}+\ln \relax (x )\right ) \sin \relax (x )}{2}+\cos \relax (x ) c_{1}\]