\[ y^{(3)}(x)+y(x) y''(x)-y'(x)^2+1=0 \] ✗ Mathematica : cpu = 0.0306784 (sec), leaf count = 0
DSolve[1 - Derivative[1][y][x]^2 + y[x]*Derivative[2][y][x] + Derivative[3][y][x] == 0,y[x],x]
, could not solve
DSolve[1 - Derivative[1][y][x]^2 + y[x]*Derivative[2][y][x] + Derivative[3][y][x] == 0, y[x], x]
✗ Maple : cpu = 0. (sec), leaf count = 0
dsolve(diff(diff(diff(y(x),x),x),x)+diff(diff(y(x),x),x)*y(x)-diff(y(x),x)^2+1=0,y(x))
, result contains DESol or ODESolStruc
\[y \left (x \right ) = \textit {\_a} \boldsymbol {\mathrm {where}}\left [\left \{\left (\frac {d^{2}}{d \textit {\_a}^{2}}\mathrm {\_}\mathrm {b}\left (\textit {\_a} \right )\right ) \textit {\_}b\left (\textit {\_a} \right )^{2}+\left (\frac {d}{d \textit {\_a}}\mathrm {\_}\mathrm {b}\left (\textit {\_a} \right )\right )^{2} \textit {\_}b\left (\textit {\_a} \right )+\left (\frac {d}{d \textit {\_a}}\mathrm {\_}\mathrm {b}\left (\textit {\_a} \right )\right ) \textit {\_}b\left (\textit {\_a} \right ) \textit {\_a} -\textit {\_}b\left (\textit {\_a} \right )^{2}+1=0\right \}, \left \{\textit {\_a} =y \left (x \right ), \textit {\_}b\left (\textit {\_a} \right )=\frac {d}{d x}y \left (x \right )\right \}, \left \{x =\int \frac {1}{\textit {\_}b\left (\textit {\_a} \right )}d \textit {\_a} +c_{1}, y \left (x \right )=\textit {\_a} \right \}\right ]\]