Internal problem ID [12571]
Book: Nonlinear Ordinary Differential Equations by D.W.Jordna and P.Smith. 4th edition 1999.
Oxford Univ. Press. NY
Section: Chapter 2. Plane autonomous systems and linearization. Problems page 79
Problem number: 2.4 (iv).
ODE order: 2.
ODE degree: 1.
CAS Maple gives this as type [[_2nd_order, _missing_x]]
\[ \boxed {x^{\prime \prime }+x^{\prime }+x+x^{3}=0} \]
✗ Solution by Maple
dsolve(diff(x(t),t$2)+diff(x(t),t)+x(t)+x(t)^3=0,x(t), singsol=all)
\[ \text {No solution found} \]
✗ Solution by Mathematica
Time used: 0.0 (sec). Leaf size: 0
DSolve[x''[t]+x'[t]+x[t]+x[t]^3==0,x[t],t,IncludeSingularSolutions -> True]
Not solved