59.10.5 problem 17.5

Internal problem ID [15069]
Book : AN INTRODUCTION TO ORDINARY DIFFERENTIAL EQUATIONS by JAMES C. ROBINSON. Cambridge University Press 2004
Section : Chapter 17, Reduction of order. Exercises page 162
Problem number : 17.5
Date solved : Thursday, October 02, 2025 at 10:02:35 AM
CAS classification : [_Hermite]

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

Using reduction of order method given that one solution is

\begin{align*} y&=x \end{align*}

✓ Maple. Time used: 0.005 (sec). Leaf size: 34

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

\[ y = -i \sqrt {\pi }\, \sqrt {2}\, {\mathrm e}^{\frac {x^{2}}{2}} c_2 +x \left (\pi c_2 \,\operatorname {erf}\left (\frac {i \sqrt {2}\, x}{2}\right )+c_1 \right ) \]

✓ Mathematica. Time used: 0.026 (sec). Leaf size: 61

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

\begin{align*} y(x)&\to -\sqrt {\frac {\pi }{2}} c_2 \sqrt {x^2} \text {erfi}\left (\frac {\sqrt {x^2}}{\sqrt {2}}\right )+c_2 e^{\frac {x^2}{2}}+\sqrt {2} c_1 x \end{align*}

✗ Sympy

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

False