\[ a y'(x) \left | y'(x)\right | +b \sin (y(x))+y''(x)=0 \] ✗ Mathematica : cpu = 33.7882 (sec), leaf count = 0
DSolve[b*Sin[y[x]] + a*Abs[Derivative[1][y][x]]*Derivative[1][y][x] + Derivative[2][y][x] == 0,y[x],x]
, could not solve
DSolve[b*Sin[y[x]] + a*Abs[Derivative[1][y][x]]*Derivative[1][y][x] + Derivative[2][y][x] == 0, y[x], x]
✗ Maple : cpu = 0. (sec), leaf count = 0
dsolve(diff(diff(y(x),x),x)+a*diff(y(x),x)*abs(diff(y(x),x))+b*sin(y(x))=0,y(x))
, result contains DESol or ODESolStruc
\[y \left (x \right ) = \textit {\_a} \:\& \text {where}\:\left [\left \{\left (\frac {d}{d \textit {\_a}}\textit {\_}b\left (\textit {\_a} \right )\right ) \textit {\_}b\left (\textit {\_a} \right )+a \textit {\_}b\left (\textit {\_a} \right ) {| \textit {\_}b\left (\textit {\_a} \right )|}+b \sin \left (\textit {\_a} \right )=0\right \}, \left \{\textit {\_a} =y \left (x \right ), \textit {\_}b\left (\textit {\_a} \right )=\frac {d}{d x}y \left (x \right )\right \}, \left \{x =\int \frac {1}{\textit {\_}b\left (\textit {\_a} \right )}d \textit {\_a} +c_{1}, y \left (x \right )=\textit {\_a} \right \}\right ]\]