7.60 problem 1650 (book 6.60)

Internal problem ID [9982]

Book: Differential Gleichungen, E. Kamke, 3rd ed. Chelsea Pub. NY, 1948
Section: Chapter 6, non-linear second order
Problem number: 1650 (book 6.60).
ODE order: 2.
ODE degree: 2.

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

\[ \boxed {y^{\prime \prime }-a \sqrt {{y^{\prime }}^{2}+1}=0} \]

Solution by Maple

Time used: 1.485 (sec). Leaf size: 36

dsolve(diff(diff(y(x),x),x)=a*(diff(y(x),x)^2+1)^(1/2),y(x), singsol=all)
 

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

Solution by Mathematica

Time used: 0.728 (sec). Leaf size: 35

DSolve[-(a*Sqrt[1 + y'[x]^2]) + y''[x] == 0,y[x],x,IncludeSingularSolutions -> True]
 

\[ y(x)\to \frac {e^{a x+c_1} \left (1+e^{-2 (a x+c_1)}\right )}{2 a}+c_2 \]