67.13.28 problem 20.4 (d)

Internal problem ID [16693]
Book : Ordinary Differential Equations. An introduction to the fundamentals. Kenneth B. Howell. second edition. CRC Press. FL, USA. 2020
Section : Chapter 20. Euler equations. Additional exercises page 382
Problem number : 20.4 (d)
Date solved : Thursday, October 02, 2025 at 01:37:49 PM
CAS classification : [[_3rd_order, _with_linear_symmetries]]

\begin{align*} -8 y+7 x y^{\prime }-3 x^{2} y^{\prime \prime }+x^{3} y^{\prime \prime \prime }&=0 \end{align*}

✓ Maple. Time used: 0.002 (sec). Leaf size: 20

ode:=x^3*diff(diff(diff(y(x),x),x),x)-3*x^2*diff(diff(y(x),x),x)+7*x*diff(y(x),x)-8*y(x) = 0; 
dsolve(ode,y(x), singsol=all);
 

\[ y = x^{2} \left (c_1 +c_2 \ln \left (x \right )+c_3 \ln \left (x \right )^{2}\right ) \]

✓ Mathematica. Time used: 0.003 (sec). Leaf size: 24

ode=x^3*D[y[x],{x,3}]-3*x^2*D[y[x],{x,2}]+7*x*D[y[x],x]-8*y[x]==0; 
ic={}; 
DSolve[{ode,ic},y[x],x,IncludeSingularSolutions->True]
 

\begin{align*} y(x)&\to x^2 \left (c_3 \log ^2(x)+c_2 \log (x)+c_1\right ) \end{align*}

✓ Sympy. Time used: 0.133 (sec). Leaf size: 19

from sympy import * 
x = symbols("x") 
y = Function("y") 
ode = Eq(x**3*Derivative(y(x), (x, 3)) - 3*x**2*Derivative(y(x), (x, 2)) + 7*x*Derivative(y(x), x) - 8*y(x),0) 
ics = {} 
dsolve(ode,func=y(x),ics=ics)
 

\[ y{\left (x \right )} = x^{2} \left (C_{1} + C_{2} \log {\left (x \right )} + C_{3} \log {\left (x \right )}^{2}\right ) \]