84.21.2 problem 13.2

Internal problem ID [22228]
Book : Schaums outline series. Differential Equations By Richard Bronson. 1973. McGraw-Hill Inc. ISBN 0-07-008009-7
Section : Chapter 13. nth Order linear homogeneous differential equations with constant coefficients. Solved problems. Page 67
Problem number : 13.2
Date solved : Thursday, October 02, 2025 at 08:36:27 PM
CAS classification : [[_high_order, _missing_x]]

\begin{align*} y^{\prime \prime \prime \prime }-9 y^{\prime \prime }+20 y&=0 \end{align*}

✓ Maple. Time used: 0.002 (sec). Leaf size: 34

ode:=diff(diff(diff(diff(y(x),x),x),x),x)-9*diff(diff(y(x),x),x)+20*y(x) = 0; 
dsolve(ode,y(x), singsol=all);
 

\[ y = c_1 \,{\mathrm e}^{2 x}+c_2 \,{\mathrm e}^{-2 x}+c_3 \,{\mathrm e}^{\sqrt {5}\, x}+c_4 \,{\mathrm e}^{-\sqrt {5}\, x} \]

✓ Mathematica. Time used: 0.002 (sec). Leaf size: 47

ode=D[y[x],{x,4}]-9*D[y[x],{x,2}]+20*y[x]==0; 
ic={}; 
DSolve[{ode,ic},y[x],x,IncludeSingularSolutions->True]
 

\begin{align*} y(x)&\to c_1 e^{\sqrt {5} x}+c_2 e^{-\sqrt {5} x}+c_3 e^{-2 x}+c_4 e^{2 x} \end{align*}

✓ Sympy. Time used: 0.074 (sec). Leaf size: 36

from sympy import * 
x = symbols("x") 
y = Function("y") 
ode = Eq(20*y(x) - 9*Derivative(y(x), (x, 2)) + Derivative(y(x), (x, 4)),0) 
ics = {} 
dsolve(ode,func=y(x),ics=ics)
 

\[ y{\left (x \right )} = C_{1} e^{- 2 x} + C_{2} e^{2 x} + C_{3} e^{- \sqrt {5} x} + C_{4} e^{\sqrt {5} x} \]