- #1
Calabi
- 140
- 2
Homework Statement
Let be ##f \in C^{1}(\mathbb{R}^{n}, \mathbb{R}^{n})## and ##a \in \mathbb{R}^{n}## with ##f(a) = a##. I'm looking for a suffisent and necessar condition on f that for all ##(x_{n})## define by ##f(x_{n}) = x_{n+1}##, then ##(x_{n})## converge.
Homework Equations
##f(a) = a##
The Attempt at a Solution
If all sequences define like this converge it's necessarly on a.
We've got the following result : if A is a complex matrix, then the seuqences define by ##X_{n+1} = AX_{n}## converge if and only if the spectral radius ##\rho{A} < 1##.
So I think we should care about the spectral radius of the jacobian of f.
By whrogting ##f(a + x_{n}) = a + df(a)x_{n} + ||x_{n}||\epsilon(x_{n})## but I get nothing.
Have you got an idea please?
Thank you in advance and have a nice afternoon.