81.10.28 problem 14-28

Internal problem ID [21623]
Book : The Differential Equations Problem Solver. VOL. I. M. Fogiel director. REA, NY. 1978. ISBN 78-63609
Section : Chapter 14. Second order homogeneous differential equations with constant coefficients. Page 297.
Problem number : 14-28
Date solved : Thursday, October 02, 2025 at 07:59:06 PM
CAS classification : [[_high_order, _missing_x]]

\begin{align*} y^{\prime \prime \prime \prime }-7 y^{\prime \prime \prime }+18 y^{\prime \prime }-20 y^{\prime }+8 y&=0 \end{align*}

✓ Maple. Time used: 0.002 (sec). Leaf size: 22

ode:=diff(diff(diff(diff(y(x),x),x),x),x)-7*diff(diff(diff(y(x),x),x),x)+18*diff(diff(y(x),x),x)-20*diff(y(x),x)+8*y(x) = 0; 
dsolve(ode,y(x), singsol=all);
 

\[ y = {\mathrm e}^{x} \left (\left (c_4 \,x^{2}+c_3 x +c_2 \right ) {\mathrm e}^{x}+c_1 \right ) \]

✓ Mathematica. Time used: 0.002 (sec). Leaf size: 28

ode=D[y[x],{x,4}]-7*D[y[x],{x,3}]+18*D[y[x],{x,2}]-20*D[y[x],x]+8*y[x]==0; 
ic={}; 
DSolve[{ode,ic},y[x],x,IncludeSingularSolutions->True]
 

\begin{align*} y(x)&\to e^x \left (e^x (x (c_4 x+c_3)+c_2)+c_1\right ) \end{align*}

✓ Sympy. Time used: 0.122 (sec). Leaf size: 19

from sympy import * 
x = symbols("x") 
y = Function("y") 
ode = Eq(8*y(x) - 20*Derivative(y(x), x) + 18*Derivative(y(x), (x, 2)) - 7*Derivative(y(x), (x, 3)) + Derivative(y(x), (x, 4)),0) 
ics = {} 
dsolve(ode,func=y(x),ics=ics)
 

\[ y{\left (x \right )} = \left (C_{1} + \left (C_{2} + x \left (C_{3} + C_{4} x\right )\right ) e^{x}\right ) e^{x} \]