4.16 problem Problem 25

Internal problem ID [2171]

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 25.
ODE order: 1.
ODE degree: 1.

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

\[ \boxed {y^{\prime }-\frac {2 \left (-x +2 y\right )}{x +y}=0} \] With initial conditions \begin {align*} [y \left (0\right ) = 2] \end {align*}

Solution by Maple

Time used: 0.859 (sec). Leaf size: 273

dsolve([diff(y(x),x)=2*(2*y(x)-x)/(x+y(x)),y(0) = 2],y(x), singsol=all)
 

\[ y \left (x \right ) = \frac {\left (3 \sqrt {3}\, x \sqrt {x \left (27 x +8\right )}+27 x^{2}+36 x +8\right )^{\frac {1}{3}}}{3}+\frac {4 x +\frac {4}{3}}{\left (3 \sqrt {3}\, x \sqrt {x \left (27 x +8\right )}+27 x^{2}+36 x +8\right )^{\frac {1}{3}}}+2 x +\frac {2}{3} \]

Solution by Mathematica

Time used: 60.261 (sec). Leaf size: 122

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

\begin{align*} y(x)\to \frac {1}{3} \left (6 x \left (\frac {2}{\sqrt [3]{3 \sqrt {3} \sqrt {x^3 (27 x+8)}+9 x (3 x+4)+8}}+1\right )+\sqrt [3]{3 \sqrt {3} \sqrt {x^3 (27 x+8)}+9 x (3 x+4)+8}+\frac {4}{\sqrt [3]{3 \sqrt {3} \sqrt {x^3 (27 x+8)}+9 x (3 x+4)+8}}+2\right ) \\ \end{align*}