2.8 problem 8

Internal problem ID [5756]

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: 8.
ODE order: 1.
ODE degree: 1.

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

\[ \boxed {-y+x y^{\prime }-\left (x +y\right ) \ln \left (\frac {x +y}{x}\right )=0} \]

Solution by Maple

Time used: 0.016 (sec). Leaf size: 12

dsolve(x*diff(y(x),x)-y(x)=(x+y(x))*ln((x+y(x))/x),y(x), singsol=all)
 

\[ y \left (x \right ) = x \left (-1+{\mathrm e}^{c_{1} x}\right ) \]

Solution by Mathematica

Time used: 0.406 (sec). Leaf size: 24

DSolve[x*y'[x]-y[x]==(x+y[x])*Log[ (x+y[x])/x],y[x],x,IncludeSingularSolutions -> True]
 

\begin{align*} y(x)\to x \left (-1+e^{e^{-c_1} x}\right ) \\ y(x)\to 0 \\ \end{align*}