20.28.7 problem 7

Internal problem ID [4069]
Book : Differential equations and linear algebra, Stephen W. Goode and Scott A Annin. Fourth edition, 2015
Section : Chapter 11, Series Solutions to Linear Differential Equations. Additional problems. Section 11.7. page 788
Problem number : 7
Date solved : Monday, January 27, 2025 at 08:07:28 AM
CAS classification : [_Lienard]

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

Using series method with expansion around

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

✓ Solution by Maple

Time used: 0.013 (sec). Leaf size: 32

Order:=6; 
dsolve(x*diff(y(x),x$2)+diff(y(x),x)+x*y(x)=0,y(x),type='series',x=0);
 

\[ y \left (x \right ) = \left (c_{2} \ln \left (x \right )+c_{1} \right ) \left (1-\frac {1}{4} x^{2}+\frac {1}{64} x^{4}+\operatorname {O}\left (x^{6}\right )\right )+\left (\frac {1}{4} x^{2}-\frac {3}{128} x^{4}+\operatorname {O}\left (x^{6}\right )\right ) c_{2} \]

✓ Solution by Mathematica

Time used: 0.003 (sec). Leaf size: 60

AsymptoticDSolveValue[x*D[y[x],{x,2}]+D[y[x],x]+x*y[x]==0,y[x],{x,0,"6"-1}]
 

\[ y(x)\to c_1 \left (\frac {x^4}{64}-\frac {x^2}{4}+1\right )+c_2 \left (-\frac {3 x^4}{128}+\frac {x^2}{4}+\left (\frac {x^4}{64}-\frac {x^2}{4}+1\right ) \log (x)\right ) \]