22.6 problem 1(f)

Internal problem ID [6084]

Book: An introduction to Ordinary Differential Equations. Earl A. Coddington. Dover. NY 1961
Section: Chapter 5. Existence and uniqueness of solutions to first order equations. Page 198
Problem number: 1(f).
ODE order: 1.
ODE degree: 1.

CAS Maple gives this as type [[_homogeneous, `class A`], _exact, _rational, [_Abel, `2nd type`, `class A`]]

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

Solution by Maple

Time used: 0.047 (sec). Leaf size: 49

dsolve((x+y(x))+(x-y(x))*diff(y(x),x)=0,y(x), singsol=all)
 

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

Solution by Mathematica

Time used: 0.449 (sec). Leaf size: 86

DSolve[(x+y[x])+(x-y[x])*y'[x]==0,y[x],x,IncludeSingularSolutions -> True]
 

\begin{align*} y(x)\to x-\sqrt {2 x^2+e^{2 c_1}} y(x)\to x+\sqrt {2 x^2+e^{2 c_1}} y(x)\to x-\sqrt {2} \sqrt {x^2} y(x)\to \sqrt {2} \sqrt {x^2}+x \end{align*}