15.10.3 problem 3

Internal problem ID [3090]
Book : Differential Equations by Alfred L. Nelson, Karl W. Folley, Max Coral. 3rd ed. DC heath. Boston. 1964
Section : Exercise 18, page 82
Problem number : 3
Date solved : Sunday, March 30, 2025 at 01:18:17 AM
CAS classification : [[_3rd_order, _missing_x]]

\begin{align*} 2 y^{\prime \prime \prime }+y^{\prime \prime }-4 y^{\prime }-3 y&=0 \end{align*}

✓ Maple. Time used: 0.003 (sec). Leaf size: 20

ode:=2*diff(diff(diff(y(x),x),x),x)+diff(diff(y(x),x),x)-4*diff(y(x),x)-3*y(x) = 0; 
dsolve(ode,y(x), singsol=all);
 

\[ y = \left (c_1 \,{\mathrm e}^{\frac {5 x}{2}}+c_3 x +c_2 \right ) {\mathrm e}^{-x} \]

✓ Mathematica. Time used: 0.004 (sec). Leaf size: 28

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

\[ y(x)\to e^{-x} \left (c_1 e^{5 x/2}+c_3 x+c_2\right ) \]

✓ Sympy. Time used: 0.171 (sec). Leaf size: 19

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

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