4.8 problem Problem 16

Internal problem ID [2163]

Book: Differential equations and linear algebra, Stephen W. Goode and Scott A Annin. Fourth edition, 2015
Section: Chapter 1, First-Order Differential Equations. Section 1.8, Change of Variables. page 79
Problem number: Problem 16.
ODE order: 1.
ODE degree: 1.

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

Solve \begin {gather*} \boxed {y^{\prime } x +\ln \relax (x ) y-\ln \relax (y) y=0} \end {gather*}

Solution by Maple

Time used: 0.013 (sec). Leaf size: 16

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

\[ y \relax (x ) = x \,{\mathrm e}^{-x c_{1}} {\mathrm e} \]

Solution by Mathematica

Time used: 0.215 (sec). Leaf size: 24

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

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