53.4.1 problem 1

Internal problem ID [8489]
Book : Elementary differential equations. By Earl D. Rainville, Phillip E. Bedient. Macmilliam Publishing Co. NY. 6th edition. 1981.
Section : CHAPTER 16. Nonlinear equations. Section 101. Independent variable missing. EXERCISES Page 324
Problem number : 1
Date solved : Wednesday, March 05, 2025 at 06:01:07 AM
CAS classification : [[_2nd_order, _missing_y], [_2nd_order, _reducible, _mu_y_y1]]

\begin{align*} y^{\prime \prime }&=x {y^{\prime }}^{3} \end{align*}

✓ Maple. Time used: 0.016 (sec). Leaf size: 37

ode:=diff(diff(y(x),x),x) = x*diff(y(x),x)^3; 
dsolve(ode,y(x), singsol=all);
 

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

✓ Mathematica. Time used: 10.839 (sec). Leaf size: 57

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

\begin{align*} y(x)\to \arctan \left (\frac {x}{\sqrt {-x^2-2 c_1}}\right )+c_2 \\ y(x)\to c_2-\arctan \left (\frac {x}{\sqrt {-x^2-2 c_1}}\right ) \\ y(x)\to c_2 \\ \end{align*}

✓ Sympy. Time used: 20.247 (sec). Leaf size: 102

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

\[ \left [ y{\left (x \right )} = C_{1} - \int \sqrt {- \frac {1}{C_{2} + x^{2}}}\, dx, \ y{\left (x \right )} = C_{1} + \int \sqrt {- \frac {1}{C_{2} + x^{2}}}\, dx, \ y{\left (x \right )} = C_{1} - \int \sqrt {- \frac {1}{C_{2} + x^{2}}}\, dx, \ y{\left (x \right )} = C_{1} + \int \sqrt {- \frac {1}{C_{2} + x^{2}}}\, dx, \ y{\left (x \right )} = C_{1} - \int \sqrt {- \frac {1}{C_{2} + x^{2}}}\, dx, \ y{\left (x \right )} = C_{1} + \int \sqrt {- \frac {1}{C_{2} + x^{2}}}\, dx\right ] \]