69.11.11 problem 270

Internal problem ID [18149]
Book : A book of problems in ordinary differential equations. M.L. KRASNOV, A.L. KISELYOV, G.I. MARKARENKO. MIR, MOSCOW. 1983
Section : Section 11. Singular solutions of differential equations. Exercises page 92
Problem number : 270
Date solved : Thursday, October 02, 2025 at 03:02:09 PM
CAS classification : [[_homogeneous, `class A`], _dAlembert]

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

✓ Maple. Time used: 0.054 (sec). Leaf size: 101

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

\begin{align*} y &= 4 x \\ y &= 0 \\ y &= \frac {c_1^{2}}{-2 x -\sqrt {2}\, c_1} \\ y &= \frac {c_1^{2}}{-2 x +\sqrt {2}\, c_1} \\ y &= -\frac {2 c_1^{2} \left (-\sqrt {2}\, c_1 +x \right )}{-2 c_1^{2}+x^{2}} \\ y &= -\frac {2 c_1^{2} \left (\sqrt {2}\, c_1 +x \right )}{-2 c_1^{2}+x^{2}} \\ \end{align*}

✓ Mathematica. Time used: 0.366 (sec). Leaf size: 61

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

\begin{align*} y(x)&\to -\frac {4 e^{-2 c_1}}{-2+e^{2 c_1} x}\\ y(x)&\to -\frac {4 e^{-2 c_1}}{2+e^{2 c_1} x}\\ y(x)&\to 0\\ y(x)&\to 4 x \end{align*}

✓ Sympy. Time used: 7.267 (sec). Leaf size: 17

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

\[ y{\left (x \right )} = - \frac {e^{2 C_{1}}}{2 \left (2 x + e^{C_{1}}\right )} \]