60.7.177 problem 1797 (book 6.206)

Internal problem ID [11727]
Book : Differential Gleichungen, E. Kamke, 3rd ed. Chelsea Pub. NY, 1948
Section : Chapter 6, non-linear second order
Problem number : 1797 (book 6.206)
Date solved : Thursday, March 13, 2025 at 09:23:08 PM
CAS classification : [_Liouville, [_2nd_order, _reducible, _mu_x_y1], [_2nd_order, _reducible, _mu_xy]]

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

✓ Maple. Time used: 0.088 (sec). Leaf size: 60

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

\begin{align*} y &= -a \\ y &= a \\ y &= \frac {\left (x +\sqrt {-a^{2}+x^{2}}\right )^{c_{1}} c_{2}^{2}+\left (x +\sqrt {-a^{2}+x^{2}}\right )^{-c_{1}} a^{2}}{2 c_{2}} \\ \end{align*}

✓ Mathematica. Time used: 8.325 (sec). Leaf size: 65

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

\[ y(x)\to \frac {1}{2} e^{c_2} \left (\sqrt {x^2-a^2}+x\right )^{-c_1}+\frac {1}{2} a^2 e^{-c_2} \left (\sqrt {x^2-a^2}+x\right )^{c_1} \]

✗ Sympy

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

NotImplementedError : The given ODE Derivative(y(x), x) - (x*(a - y(x))*(a + y(x))*(a**2 - x**2) + sqrt(-(a - y(x))*(a + y(x))*(4*a**4*y(x)*Derivative(y(x), (x, 2)) - 8*a**2*x**2*y(x)*Derivative(y(x), (x, 2)) - a**2*x**2 + 4*x**4*y(x)*Derivative(y(x), (x, 2)) + x**2*y(x)**2))*(a - x)*(a + x))/(2*(a - x)*(a + x)*(a**2 - x**2)*y(x)) cannot be solved by the factorable group method