83.11.8 problem 8

Internal problem ID [21997]
Book : Differential Equations By Kaj L. Nielsen. Second edition 1966. Barnes and nobel. 66-28306
Section : Chapter VI. Linear equations with constant coefficients. Ex. XIII at page 106
Problem number : 8
Date solved : Thursday, October 02, 2025 at 08:21:32 PM
CAS classification : [[_high_order, _missing_x]]

\begin{align*} y^{\prime \prime \prime \prime }-8 y^{\prime \prime \prime }+42 y^{\prime \prime }-104 y^{\prime }+169 y&=0 \end{align*}

✓ Maple. Time used: 0.001 (sec). Leaf size: 30

ode:=diff(diff(diff(diff(y(x),x),x),x),x)-8*diff(diff(diff(y(x),x),x),x)+42*diff(diff(y(x),x),x)-104*diff(y(x),x)+169*y(x) = 0; 
dsolve(ode,y(x), singsol=all);
 

\[ y = {\mathrm e}^{2 x} \left (\left (c_4 x +c_2 \right ) \cos \left (3 x \right )+\sin \left (3 x \right ) \left (c_3 x +c_1 \right )\right ) \]

✓ Mathematica. Time used: 0.002 (sec). Leaf size: 36

ode=D[y[x],{x,4}]-8*D[y[x],{x,3}]+42*D[y[x],{x,2}]-104*D[y[x],x]+169*y[x]==0; 
ic={}; 
DSolve[{ode,ic},y[x],x,IncludeSingularSolutions->True]
 

\begin{align*} y(x)&\to e^{2 x} ((c_4 x+c_3) \cos (3 x)+(c_2 x+c_1) \sin (3 x)) \end{align*}

✓ Sympy. Time used: 0.150 (sec). Leaf size: 27

from sympy import * 
x = symbols("x") 
y = Function("y") 
ode = Eq(169*y(x) - 104*Derivative(y(x), x) + 42*Derivative(y(x), (x, 2)) - 8*Derivative(y(x), (x, 3)) + Derivative(y(x), (x, 4)),0) 
ics = {} 
dsolve(ode,func=y(x),ics=ics)
 

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