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Math 6410 • ODE

Fall 1992 • Question 1

Let \(E\) be an open subset of \(\mathbb {R}^n\). Let \(f\) be a continuously differentiable function mapping \(E\) into \(\mathbb {R}^n\), and let \(x_0\) belong to \(E\).

  1. Use the method of successive approximations to prove that the initial value problem \(x'=f(x)\), \(x(0)=x_0\) has a unique solution on some interval \([-a,a]\), and give an estimate for \(a\).
  2. Suggest how the result in a) can be used to prove a similar result for the nonautonomous case.

Raw LaTeX

Let \(E\) be an open subset of \(\R^n\). Let \(f\) be a continuously
differentiable function mapping \(E\) into \(\R^n\), and let \(x_0\) belong to \(E\).

\begin{enumerate}
\item[(a)] Use the method of successive approximations to prove that the initial
value problem \(x'=f(x)\), \(x(0)=x_0\) has a unique solution on some interval
\([-a,a]\), and give an estimate for \(a\).

\item[(b)] Suggest how the result in a) can be used to prove a similar result for the
nonautonomous case.
\end{enumerate}