60.7.7 problem 1597 (6.7)

Internal problem ID [11557]
Book : Differential Gleichungen, E. Kamke, 3rd ed. Chelsea Pub. NY, 1948
Section : Chapter 6, non-linear second order
Problem number : 1597 (6.7)
Date solved : Wednesday, March 05, 2025 at 02:28:00 PM
CAS classification : [[_2nd_order, _missing_x], [_2nd_order, _reducible, _mu_x_y1]]

\begin{align*} y^{\prime \prime }-a y^{3}&=0 \end{align*}

Maple. Time used: 0.018 (sec). Leaf size: 25
ode:=diff(diff(y(x),x),x)-a*y(x)^3 = 0; 
dsolve(ode,y(x), singsol=all);
 
\[ y = c_{2} \operatorname {JacobiSN}\left (\frac {\left (\sqrt {2}\, \sqrt {-a}\, x +2 c_{1} \right ) c_{2}}{2}, i\right ) \]
Mathematica. Time used: 61.202 (sec). Leaf size: 131
ode=-(a*y[x]^3) + D[y[x],{x,2}] == 0; 
ic={}; 
DSolve[{ode,ic},y[x],x,IncludeSingularSolutions->True]
 
\begin{align*} y(x)\to -\frac {i \sqrt [4]{2} \text {sn}\left (\left .-\frac {(1-i) \sqrt {\sqrt {a} \sqrt {c_1} (x+c_2){}^2}}{2^{3/4}}\right |-1\right )}{\sqrt {\frac {i \sqrt {a}}{\sqrt {c_1}}}} \\ y(x)\to \frac {i \sqrt [4]{2} \text {sn}\left (\left .-\frac {(1-i) \sqrt {\sqrt {a} \sqrt {c_1} (x+c_2){}^2}}{2^{3/4}}\right |-1\right )}{\sqrt {\frac {i \sqrt {a}}{\sqrt {c_1}}}} \\ \end{align*}
Sympy. Time used: 14.741 (sec). Leaf size: 88
from sympy import * 
x = symbols("x") 
a = symbols("a") 
y = Function("y") 
ode = Eq(-a*y(x)**3 + Derivative(y(x), (x, 2)),0) 
ics = {} 
dsolve(ode,func=y(x),ics=ics)
 
\[ \left [ \frac {y{\left (x \right )} \Gamma \left (\frac {1}{4}\right ) {{}_{2}F_{1}\left (\begin {matrix} \frac {1}{4}, \frac {1}{2} \\ \frac {5}{4} \end {matrix}\middle | {\frac {a e^{i \pi } y^{4}{\left (x \right )}}{2 C_{1}}} \right )}}{4 \sqrt {C_{1}} \Gamma \left (\frac {5}{4}\right )} = C_{2} + x, \ \frac {y{\left (x \right )} \Gamma \left (\frac {1}{4}\right ) {{}_{2}F_{1}\left (\begin {matrix} \frac {1}{4}, \frac {1}{2} \\ \frac {5}{4} \end {matrix}\middle | {\frac {a e^{i \pi } y^{4}{\left (x \right )}}{2 C_{1}}} \right )}}{4 \sqrt {C_{1}} \Gamma \left (\frac {5}{4}\right )} = C_{2} - x\right ] \]