1.3 problem 3

Internal problem ID [4175]

Book: A treatise on ordinary and partial differential equations by William Woolsey Johnson. 1913
Section: Chapter 1, Nature and meaning of a differential equation between two variables. page 12
Problem number: 3.
ODE order: 1.
ODE degree: 2.

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

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

Solution by Maple

Time used: 0.313 (sec). Leaf size: 75

dsolve(y(x)*diff(y(x),x)^2+2*x*diff(y(x),x)-y(x)=0,y(x), singsol=all)
 

\begin{align*} y \relax (x ) = -i x \\ y \relax (x ) = i x \\ y \relax (x ) = 0 \\ y \relax (x ) = \sqrt {-2 c_{1} x +c_{1}^{2}} \\ y \relax (x ) = \sqrt {2 c_{1} x +c_{1}^{2}} \\ y \relax (x ) = -\sqrt {-2 c_{1} x +c_{1}^{2}} \\ y \relax (x ) = -\sqrt {2 c_{1} x +c_{1}^{2}} \\ \end{align*}

Solution by Mathematica

Time used: 0.778 (sec). Leaf size: 126

DSolve[y[x]*(y'[x])^2+2*x*y'[x]-y[x]==0,y[x],x,IncludeSingularSolutions -> True]
 

\begin{align*} y(x)\to -e^{\frac {c_1}{2}} \sqrt {-2 x+e^{c_1}} \\ y(x)\to e^{\frac {c_1}{2}} \sqrt {-2 x+e^{c_1}} \\ y(x)\to -e^{\frac {c_1}{2}} \sqrt {2 x+e^{c_1}} \\ y(x)\to e^{\frac {c_1}{2}} \sqrt {2 x+e^{c_1}} \\ y(x)\to 0 \\ y(x)\to -i x \\ y(x)\to i x \\ \end{align*}