81.8.2 problem 9-2

Internal problem ID [21585]
Book : The Differential Equations Problem Solver. VOL. I. M. Fogiel director. REA, NY. 1978. ISBN 78-63609
Section : Chapter 9. Clairaut Equation. Page 133.
Problem number : 9-2
Date solved : Thursday, October 02, 2025 at 07:58:40 PM
CAS classification : [[_1st_order, _with_linear_symmetries], _rational, _Clairaut]

\begin{align*} {y^{\prime }}^{2} \left (x^{2}-1\right )-2 x y y^{\prime }+y^{2}-1&=0 \end{align*}
Maple. Time used: 0.039 (sec). Leaf size: 57
ode:=(x^2-1)*diff(y(x),x)^2-2*x*y(x)*diff(y(x),x)+y(x)^2-1 = 0; 
dsolve(ode,y(x), singsol=all);
 
\begin{align*} y &= \sqrt {-x^{2}+1} \\ y &= -\sqrt {-x^{2}+1} \\ y &= c_1 x -\sqrt {c_1^{2}+1} \\ y &= c_1 x +\sqrt {c_1^{2}+1} \\ \end{align*}
Mathematica. Time used: 0.039 (sec). Leaf size: 73
ode=(x^2-1)*D[y[x],x]^2-2*x*y[x]*D[y[x],x]+y[x]^2-1==0; 
ic={}; 
DSolve[{ode,ic},y[x],x,IncludeSingularSolutions->True]
 
\begin{align*} y(x)&\to c_1 x-\sqrt {1+c_1{}^2}\\ y(x)&\to c_1 x+\sqrt {1+c_1{}^2}\\ y(x)&\to -\sqrt {1-x^2}\\ y(x)&\to \sqrt {1-x^2} \end{align*}
Sympy
from sympy import * 
x = symbols("x") 
y = Function("y") 
ode = Eq(-2*x*y(x)*Derivative(y(x), x) + (x**2 - 1)*Derivative(y(x), x)**2 + y(x)**2 - 1,0) 
ics = {} 
dsolve(ode,func=y(x),ics=ics)
 
Timed Out