Exercises
[0DK]Let \(f(x)=x-x^ 3\) and \(x_ 0β{\mathbb {R}}\), and \((x_ n )_{nβ{\mathbb {N}}}\) a sequence defined by recurrence by \(x_{n+1}=f(x_ n)\). Prove that there is a \(π{\gt}0\) such that if \(|x_ 0|{\lt}π\) then \(x_ nβ 0\), while if \(|x_ 0|{\gt}π\) then \(|x_ n|β β\); and possibly calculate this \(π\).
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