2.20 problem 20

Internal problem ID [5015]

Book: Ordinary differential equations and calculus of variations. Makarets and Reshetnyak. Wold Scientific. Singapore. 1995
Section: Chapter 1. First order differential equations. Section 1.2 Homogeneous equations problems. page 12
Problem number: 20.
ODE order: 1.
ODE degree: 1.

CAS Maple gives this as type [[_homogeneous, class A], _rational, _dAlembert]

Solve \begin {gather*} \boxed {x y^{\prime }-y-\sqrt {y^{2}-x^{2}}=0} \end {gather*}

Solution by Maple

Time used: 0.005 (sec). Leaf size: 29

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

\[ \frac {y \relax (x )}{x^{2}}+\frac {\sqrt {y \relax (x )^{2}-x^{2}}}{x^{2}}-c_{1} = 0 \]

Solution by Mathematica

Time used: 0.467 (sec). Leaf size: 13

DSolve[x*y'[x]==y[x]+Sqrt[y[x]^2-x^2],y[x],x,IncludeSingularSolutions -> True]
 

\begin{align*} y(x)\to x \cosh (\log (x)+c_1) \\ \end{align*}