7.209 problem 1800 (book 6.209)

Internal problem ID [10131]

Book: Differential Gleichungen, E. Kamke, 3rd ed. Chelsea Pub. NY, 1948
Section: Chapter 6, non-linear second order
Problem number: 1800 (book 6.209).
ODE order: 2.
ODE degree: 1.

CAS Maple gives this as type [[_2nd_order, _missing_x], [_2nd_order, _reducible, _mu_x_y1]]

\[ \boxed {y^{3} y^{\prime \prime }=a} \]

Solution by Maple

Time used: 17.25 (sec). Leaf size: 70

dsolve(y(x)^3*diff(diff(y(x),x),x)-a=0,y(x), singsol=all)
 

\begin{align*} y \left (x \right ) = \frac {\sqrt {c_{1} \left (c_{1}^{2} c_{2}^{2}+2 c_{1}^{2} c_{2} x +c_{1}^{2} x^{2}+a \right )}}{c_{1}} y \left (x \right ) = -\frac {\sqrt {c_{1} \left (c_{1}^{2} c_{2}^{2}+2 c_{1}^{2} c_{2} x +c_{1}^{2} x^{2}+a \right )}}{c_{1}} \end{align*}

Solution by Mathematica

Time used: 4.192 (sec). Leaf size: 63

DSolve[-a + y[x]^3*y''[x] == 0,y[x],x,IncludeSingularSolutions -> True]
 

\begin{align*} y(x)\to -\frac {\sqrt {a+c_1{}^2 (x+c_2){}^2}}{\sqrt {c_1}} y(x)\to \frac {\sqrt {a+c_1{}^2 (x+c_2){}^2}}{\sqrt {c_1}} y(x)\to \text {Indeterminate} \end{align*}