28.4.7 problem 7

Internal problem ID [7196]
Book : A treatise on ordinary and partial differential equations by William Woolsey Johnson. 1913
Section : Chapter VII, Solutions in series. Examples XV. page 194
Problem number : 7
Date solved : Tuesday, September 30, 2025 at 04:25:20 PM
CAS classification : [[_elliptic, _class_I]]

\begin{align*} x \left (-x^{2}+1\right ) y^{\prime \prime }+\left (-3 x^{2}+1\right ) y^{\prime }-x y&=0 \end{align*}

Using series method with expansion around

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

✓ Maple. Time used: 0.032 (sec). Leaf size: 32

Order:=6; 
ode:=x*(-x^2+1)*diff(diff(y(x),x),x)+(-3*x^2+1)*diff(y(x),x)-x*y(x) = 0; 
dsolve(ode,y(x),type='series',x=0);
 

\[ y = \left (c_2 \ln \left (x \right )+c_1 \right ) \left (1+\frac {1}{4} x^{2}+\frac {9}{64} x^{4}+\operatorname {O}\left (x^{6}\right )\right )+\left (\frac {1}{4} x^{2}+\frac {21}{128} x^{4}+\operatorname {O}\left (x^{6}\right )\right ) c_2 \]

✓ Mathematica. Time used: 0.004 (sec). Leaf size: 60

ode=x*(1-x^2)*D[y[x],{x,2}]+(1-3*x^2)*D[y[x],x]-x*y[x]==0; 
ic={}; 
AsymptoticDSolveValue[{ode,ic},y[x],{x,0,5}]
 

\[ y(x)\to c_1 \left (\frac {9 x^4}{64}+\frac {x^2}{4}+1\right )+c_2 \left (\frac {21 x^4}{128}+\frac {x^2}{4}+\left (\frac {9 x^4}{64}+\frac {x^2}{4}+1\right ) \log (x)\right ) \]

✓ Sympy. Time used: 0.406 (sec). Leaf size: 7

from sympy import * 
x = symbols("x") 
y = Function("y") 
ode = Eq(x*(1 - x**2)*Derivative(y(x), (x, 2)) - x*y(x) + (1 - 3*x**2)*Derivative(y(x), x),0) 
ics = {} 
dsolve(ode,func=y(x),ics=ics,hint="2nd_power_series_regular",x0=0,n=6)
 

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