20.4.2 problem Problem 10

Internal problem ID [3637]
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 10
Date solved : Tuesday, March 04, 2025 at 04:55:32 PM
CAS classification : [[_homogeneous, `class A`], _rational, [_Abel, `2nd type`, `class A`]]

\begin{align*} \left (3 x -y\right ) y^{\prime }&=3 y \end{align*}

✓ Maple. Time used: 0.016 (sec). Leaf size: 17

ode:=(3*x-y(x))*diff(y(x),x) = 3*y(x); 
dsolve(ode,y(x), singsol=all);
 

\[ y \left (x \right ) = -\frac {3 x}{\operatorname {LambertW}\left (-3 x \,{\mathrm e}^{-3 c_{1}}\right )} \]

✓ Mathematica. Time used: 5.724 (sec). Leaf size: 25

ode=(3*x-y[x])*D[y[x],x]==3*y[x]; 
ic={}; 
DSolve[{ode,ic},y[x],x,IncludeSingularSolutions->True]
 

\begin{align*} y(x)\to -\frac {3 x}{W\left (-3 e^{-c_1} x\right )} \\ y(x)\to 0 \\ \end{align*}

✓ Sympy. Time used: 0.642 (sec). Leaf size: 15

from sympy import * 
x = symbols("x") 
y = Function("y") 
ode = Eq((3*x - y(x))*Derivative(y(x), x) - 3*y(x),0) 
ics = {} 
dsolve(ode,func=y(x),ics=ics)
 

\[ y{\left (x \right )} = e^{C_{1} + W\left (- 3 x e^{- C_{1}}\right )} \]