58.1.46 problem 46
Internal
problem
ID
[9117]
Book
:
Second
order
enumerated
odes
Section
:
section
1
Problem
number
:
46
Date
solved
:
Sunday, March 30, 2025 at 02:07:39 PM
CAS
classification
:
[[_2nd_order, _missing_x]]
\begin{align*} y {y^{\prime \prime }}^{2}+{y^{\prime }}^{3}&=0 \end{align*}
✓ Maple. Time used: 1.138 (sec). Leaf size: 178
ode:=y(x)*diff(diff(y(x),x),x)^2+diff(y(x),x)^3 = 0;
dsolve(ode,y(x), singsol=all);
\begin{align*}
y &= c_1 \\
y &= 0 \\
y &= {\mathrm e}^{-\int {\mathrm e}^{2 \operatorname {RootOf}\left ({\mathrm e}^{\textit {\_Z}} \ln \left (\left ({\mathrm e}^{\textit {\_Z}}-1\right )^{2}\right )+c_1 \,{\mathrm e}^{\textit {\_Z}}-2 \,{\mathrm e}^{\textit {\_Z}} \textit {\_Z} +x \,{\mathrm e}^{\textit {\_Z}}-\ln \left (\left ({\mathrm e}^{\textit {\_Z}}-1\right )^{2}\right )-c_1 +2 \textit {\_Z} -x +2\right )}d x +2 \int {\mathrm e}^{\operatorname {RootOf}\left ({\mathrm e}^{\textit {\_Z}} \ln \left (\left ({\mathrm e}^{\textit {\_Z}}-1\right )^{2}\right )+c_1 \,{\mathrm e}^{\textit {\_Z}}-2 \,{\mathrm e}^{\textit {\_Z}} \textit {\_Z} +x \,{\mathrm e}^{\textit {\_Z}}-\ln \left (\left ({\mathrm e}^{\textit {\_Z}}-1\right )^{2}\right )-c_1 +2 \textit {\_Z} -x +2\right )}d x -x +c_2} \\
y &= \frac {c_2 {\left (\operatorname {LambertW}\left (c_1 \,{\mathrm e}^{-1+\frac {x}{2}}\right )+1\right )}^{2}}{\operatorname {LambertW}\left (c_1 \,{\mathrm e}^{-1+\frac {x}{2}}\right )^{2}} \\
y &= \frac {c_2 {\left (\operatorname {LambertW}\left (-c_1 \,{\mathrm e}^{-1+\frac {x}{2}}\right )+1\right )}^{2}}{\operatorname {LambertW}\left (-c_1 \,{\mathrm e}^{-1+\frac {x}{2}}\right )^{2}} \\
\end{align*}
✓ Mathematica. Time used: 1.974 (sec). Leaf size: 361
ode=y[x]*D[y[x],{x,2}]^2+D[y[x],x]^3==0;
ic={};
DSolve[{ode,ic},y[x],x,IncludeSingularSolutions->True]
\begin{align*}
y(x)\to \text {InverseFunction}\left [-4 \left (\frac {1}{2} \log \left (2 \sqrt {\text {$\#$1}}-i c_1\right )-\frac {i c_1}{2 \left (2 \sqrt {\text {$\#$1}}-i c_1\right )}\right )\&\right ][x+c_2] \\
y(x)\to \text {InverseFunction}\left [-4 \left (\frac {i c_1}{2 \left (2 \sqrt {\text {$\#$1}}+i c_1\right )}+\frac {1}{2} \log \left (2 \sqrt {\text {$\#$1}}+i c_1\right )\right )\&\right ][x+c_2] \\
y(x)\to \text {InverseFunction}\left [-4 \left (\frac {1}{2} \log \left (2 \sqrt {\text {$\#$1}}-i (-c_1)\right )-\frac {i (-c_1)}{2 \left (2 \sqrt {\text {$\#$1}}-i (-c_1)\right )}\right )\&\right ][x+c_2] \\
y(x)\to \text {InverseFunction}\left [-4 \left (\frac {i (-c_1)}{2 \left (2 \sqrt {\text {$\#$1}}+i (-1) c_1\right )}+\frac {1}{2} \log \left (2 \sqrt {\text {$\#$1}}+i (-1) c_1\right )\right )\&\right ][x+c_2] \\
y(x)\to \text {InverseFunction}\left [-4 \left (\frac {1}{2} \log \left (2 \sqrt {\text {$\#$1}}-i c_1\right )-\frac {i c_1}{2 \left (2 \sqrt {\text {$\#$1}}-i c_1\right )}\right )\&\right ][x+c_2] \\
y(x)\to \text {InverseFunction}\left [-4 \left (\frac {i c_1}{2 \left (2 \sqrt {\text {$\#$1}}+i c_1\right )}+\frac {1}{2} \log \left (2 \sqrt {\text {$\#$1}}+i c_1\right )\right )\&\right ][x+c_2] \\
\end{align*}
✗ Sympy
from sympy import *
x = symbols("x")
y = Function("y")
ode = Eq(y(x)*Derivative(y(x), (x, 2))**2 + Derivative(y(x), x)**3,0)
ics = {}
dsolve(ode,func=y(x),ics=ics)
NotImplementedError : The given ODE (-y(x)*Derivative(y(x), (x, 2))**2)**(1/3)/2 - sqrt(3)*I*(-y(x)*Derivative(y(x), (x, 2))**2)**(1/3)/2 + Derivative(y(x), x) cannot be solved by the factorable group method