74.17.15 problem 15

Internal problem ID [16467]
Book : INTRODUCTORY DIFFERENTIAL EQUATIONS. Martha L. Abell, James P. Braselton. Fourth edition 2014. ElScAe. 2014
Section : Chapter 4. Higher Order Equations. Exercises 4.9, page 215
Problem number : 15
Date solved : Thursday, March 13, 2025 at 08:14:23 AM
CAS classification : [[_Emden, _Fowler]]

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

Using series method with expansion around

\begin{align*} 0 \end{align*}

✓ Maple. Time used: 0.073 (sec). Leaf size: 25

Order:=6; 
ode:=x^2*diff(diff(y(x),x),x)+7*x*diff(y(x),x)-7*y(x) = 0; 
dsolve(ode,y(x),type='series',x=0);
 

\[ y = c_{1} x \left (1+\operatorname {O}\left (x^{6}\right )\right )+\frac {c_{2} \left (-203212800+\operatorname {O}\left (x^{6}\right )\right )}{x^{7}} \]

✓ Mathematica. Time used: 0.004 (sec). Leaf size: 14

ode=x^2*D[y[x],{x,2}]+7*x*D[y[x],x]-7*y[x]==0; 
ic={}; 
AsymptoticDSolveValue[{ode,ic},y[x],{x,0,5}]
 

\[ y(x)\to \frac {c_1}{x^7}+c_2 x \]

✓ Sympy. Time used: 0.731 (sec). Leaf size: 14

from sympy import * 
x = symbols("x") 
y = Function("y") 
ode = Eq(x**2*Derivative(y(x), (x, 2)) + 7*x*Derivative(y(x), x) - 7*y(x),0) 
ics = {} 
dsolve(ode,func=y(x),ics=ics,hint="2nd_power_series_regular",x0=0,n=6)
 

\[ y{\left (x \right )} = C_{2} x + \frac {C_{1}}{x^{7}} + O\left (x^{6}\right ) \]