Internal problem ID [9301]
Book: Differential Gleichungen, E. Kamke, 3rd ed. Chelsea Pub. NY, 1948
Section: Chapter 6, non-linear second order
Problem number: 1722.
ODE order: 2.
ODE degree: 1.
CAS Maple gives this as type [[_2nd_order, _missing_x]]
Solve \begin {gather*} \boxed {y^{\prime \prime } y-\left (y^{\prime }\right )^{2}-1-2 a y \left (\left (y^{\prime }\right )^{2}+1\right )^{\frac {3}{2}}=0} \end {gather*}
✓ Solution by Maple
Time used: 0.401 (sec). Leaf size: 116
dsolve(diff(diff(y(x),x),x)*y(x)-diff(y(x),x)^2-1-2*a*y(x)*(diff(y(x),x)^2+1)^(3/2)=0,y(x), singsol=all)
\begin{align*} y \relax (x ) = -i x +c_{1} \\ y \relax (x ) = i x +c_{1} \\ \int _{}^{y \relax (x )}\frac {\textit {\_a}^{2} a +c_{1}}{\sqrt {-a^{2} \textit {\_a}^{4}-2 \textit {\_a}^{2} a c_{1}+\textit {\_a}^{2}-c_{1}^{2}}}d \textit {\_a} -x -c_{2} = 0 \\ \int _{}^{y \relax (x )}-\frac {\textit {\_a}^{2} a +c_{1}}{\sqrt {-a^{2} \textit {\_a}^{4}-2 \textit {\_a}^{2} a c_{1}+\textit {\_a}^{2}-c_{1}^{2}}}d \textit {\_a} -x -c_{2} = 0 \\ \end{align*}
✓ Solution by Mathematica
Time used: 0.852 (sec). Leaf size: 697
DSolve[-1 - y'[x]^2 - 2*a*y[x]*(1 + y'[x]^2)^(3/2) + y[x]*y''[x] == 0,y[x],x,IncludeSingularSolutions -> True]
\begin{align*} y(x)\to \text {InverseFunction}\left [-\frac {\sqrt {1-\frac {2 \text {$\#$1}^2 a^2}{-2 a c_1+\sqrt {1-4 a c_1}+1}} \sqrt {1+\frac {2 \text {$\#$1}^2 a^2}{2 a c_1+\sqrt {1-4 a c_1}-1}} \left (\left (-2 a c_1+\sqrt {1-4 a c_1}+1\right ) E\left (i \sinh ^{-1}\left (\sqrt {2} \sqrt {\frac {a^2}{2 a c_1+\sqrt {1-4 a c_1}-1}} \text {$\#$1}\right )|-\frac {2 a c_1+\sqrt {1-4 a c_1}-1}{-2 a c_1+\sqrt {1-4 a c_1}+1}\right )-\left (1+\sqrt {1-4 a c_1}\right ) F\left (i \sinh ^{-1}\left (\sqrt {2} \sqrt {\frac {a^2}{2 a c_1+\sqrt {1-4 a c_1}-1}} \text {$\#$1}\right )|-\frac {2 a c_1+\sqrt {1-4 a c_1}-1}{-2 a c_1+\sqrt {1-4 a c_1}+1}\right )\right )}{2 \sqrt {2} a \sqrt {\frac {a^2}{2 a c_1+\sqrt {1-4 a c_1}-1}} \sqrt {\text {$\#$1}^4 a^2+\text {$\#$1}^2 (-1+2 a c_1)+c_1{}^2}}\&\right ][x+c_2] \\ y(x)\to \text {InverseFunction}\left [\frac {\sqrt {1-\frac {2 \text {$\#$1}^2 a^2}{-2 a c_1+\sqrt {1-4 a c_1}+1}} \sqrt {1+\frac {2 \text {$\#$1}^2 a^2}{2 a c_1+\sqrt {1-4 a c_1}-1}} \left (\left (-2 a c_1+\sqrt {1-4 a c_1}+1\right ) E\left (i \sinh ^{-1}\left (\sqrt {2} \sqrt {\frac {a^2}{2 a c_1+\sqrt {1-4 a c_1}-1}} \text {$\#$1}\right )|-\frac {2 a c_1+\sqrt {1-4 a c_1}-1}{-2 a c_1+\sqrt {1-4 a c_1}+1}\right )-\left (1+\sqrt {1-4 a c_1}\right ) F\left (i \sinh ^{-1}\left (\sqrt {2} \sqrt {\frac {a^2}{2 a c_1+\sqrt {1-4 a c_1}-1}} \text {$\#$1}\right )|-\frac {2 a c_1+\sqrt {1-4 a c_1}-1}{-2 a c_1+\sqrt {1-4 a c_1}+1}\right )\right )}{2 \sqrt {2} a \sqrt {\frac {a^2}{2 a c_1+\sqrt {1-4 a c_1}-1}} \sqrt {\text {$\#$1}^4 a^2+\text {$\#$1}^2 (-1+2 a c_1)+c_1{}^2}}\&\right ][x+c_2] \\ \end{align*}