37.7 problem 1120

Internal problem ID [3813]

Book: Ordinary differential equations and their solutions. By George Moseley Murphy. 1960
Section: Various 37
Problem number: 1120.
ODE order: 1.
ODE degree: 2.

CAS Maple gives this as type [_quadrature]

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

Solution by Maple

Time used: 0.119 (sec). Leaf size: 33

dsolve(sqrt(1+diff(y(x),x)^2) = x*diff(y(x),x),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: 0.011 (sec). Leaf size: 41

DSolve[Sqrt[1+(y'[x])^2]==x y'[x],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*}