6.9 problem 9

Internal problem ID [3906]

Book: Differential Equations, By George Boole F.R.S. 1865
Section: Chapter 7
Problem number: 9.
ODE order: 1.
ODE degree: 2.

CAS Maple gives this as type [_quadrature]

Solve \begin {gather*} \boxed {y^{\prime }-\frac {\sqrt {\left (y^{\prime }\right )^{2}+1}}{x}=0} \end {gather*}

Solution by Maple

Time used: 0.203 (sec). Leaf size: 33

dsolve(diff(y(x),x)-1/x*sqrt(1+(diff(y(x),x))^2)=0,y(x), singsol=all)
 

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

Solution by Mathematica

Time used: 0.012 (sec). Leaf size: 41

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

\begin{align*} y(x)\to -\tanh ^{-1}\left (\frac {x}{\sqrt {x^2-1}}\right )+c_1 \\ y(x)\to \tanh ^{-1}\left (\frac {x}{\sqrt {x^2-1}}\right )+c_1 \\ \end{align*}