Apply this theorem to the system \[ \begin {aligned} u'&=-v\\ v'&=-v+g(u)\\ x&=\begin {pmatrix}u\\v\end {pmatrix}, \end {aligned} \] where \(g:\mathbb {R}\to \mathbb {R}\) is a \(C^1\) function such that \[ ug(u)>0,\quad u\ne 0, \] using \[ \phi (u,v)=\frac {v^2}{2}+\int _0^u g(\xi )\,d\xi . \] What is your conclusion?
Question
Math 6410 • ODE
Fall 1996 • Question 12