Zeros of an Iterated Quadratic

8/10functionsRecursionalgebraInduction

Problem

Let f1(x)=f(x)=x(x1)f_1(x)=f(x)=x(x-1) and fn(x)=f(fn1(x))f_n(x)=f(f_{n-1}(x)) for n2n\geqslant 2. Prove:

1. For x>2x>2, fn(x)f_n(x) has no zeros. 2. For 1x21\leqslant x\leqslant 2, fn(x)f_n(x) has at least nn zeros.

Answer

Solution

Difficulty8/10
Topicsfunctions, Recursion, algebra, Induction

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