\[ a e^x \sqrt {y(x)}+y''(x)=0 \] ✗ Mathematica : cpu = 20.1682 (sec), leaf count = 0 , could not solve
DSolve[a*E^x*Sqrt[y[x]] + Derivative[2][y][x] == 0, y[x], x]
✓ Maple : cpu = 1.266 (sec), leaf count = 104
\[\left \{y \left (x \right ) = \mathit {ODESolStruc} \left (\textit {\_a} \,{\mathrm e}^{2 c_{1}+\int 2 \textit {\_}b\left (\textit {\_a} \right )d \textit {\_a}}, \left [\left \{\frac {d}{d \textit {\_a}}\mathrm {\_}\mathrm {b}\left (\textit {\_a} \right )=\left (\sqrt {\textit {\_a}}\, a \textit {\_}b\left (\textit {\_a} \right )+4 \textit {\_a} \textit {\_}b\left (\textit {\_a} \right )+4\right ) \textit {\_}b\left (\textit {\_a} \right )^{2}\right \}, \left \{\textit {\_a} ={\mathrm e}^{-2 x} y \left (x \right ), \textit {\_}b\left (\textit {\_a} \right )=\frac {{\mathrm e}^{2 x}}{\frac {d}{d x}y \left (x \right )-2 y \left (x \right )}\right \}, \left \{x =c_{1}+\int \textit {\_}b\left (\textit {\_a} \right )d \textit {\_a} , y \left (x \right )=\textit {\_a} \,{\mathrm e}^{2 c_{1}+\int 2 \textit {\_}b\left (\textit {\_a} \right )d \textit {\_a}}\right \}\right ]\right )\right \}\]