29.30.10 problem 869

Internal problem ID [5450]
Book : Ordinary differential equations and their solutions. By George Moseley Murphy. 1960
Section : Various 30
Problem number : 869
Date solved : Sunday, March 30, 2025 at 08:13:52 AM
CAS classification : [[_homogeneous, `class G`]]

\begin{align*} x {y^{\prime }}^{2}-3 y y^{\prime }+9 x^{2}&=0 \end{align*}

✓ Maple. Time used: 0.247 (sec). Leaf size: 51

ode:=x*diff(y(x),x)^2-3*y(x)*diff(y(x),x)+9*x^2 = 0; 
dsolve(ode,y(x), singsol=all);
 

\begin{align*} y &= -2 x^{{3}/{2}} \\ y &= 2 x^{{3}/{2}} \\ y &= \frac {c_1^{2} x^{3}+4}{2 c_1} \\ y &= \frac {4 x^{3}+c_1^{2}}{2 c_1} \\ \end{align*}

✓ Mathematica. Time used: 0.302 (sec). Leaf size: 79

ode=x (D[y[x],x])^2-3 y[x] D[y[x],x]+9 x^2==0; 
ic={}; 
DSolve[{ode,ic},y[x],x,IncludeSingularSolutions->True]
 

\begin{align*} y(x)\to -\frac {1}{2} e^{-\frac {3 c_1}{2}} \left (4 x^3+e^{3 c_1}\right ) \\ y(x)\to \frac {1}{2} e^{-\frac {3 c_1}{2}} \left (4 x^3+e^{3 c_1}\right ) \\ y(x)\to -2 x^{3/2} \\ y(x)\to 2 x^{3/2} \\ \end{align*}

✗ Sympy

from sympy import * 
x = symbols("x") 
y = Function("y") 
ode = Eq(9*x**2 + x*Derivative(y(x), x)**2 - 3*y(x)*Derivative(y(x), x),0) 
ics = {} 
dsolve(ode,func=y(x),ics=ics)
 

NotImplementedError : The given ODE Derivative(y(x), x) - 3*(sqrt(-4*x**3 + y(x)**2) + y(x))/(2*x) cannot be solved by the factorable group method