I want to show that limk→∞xk=0 for x∈(0,1).
This makes intuitive sense but I can't figure out how I should go about proving it. Using the epsilon-delta definition I'd need to show that for every ϵ>0 there is M∈N such that
|xk|<ϵ where k≥M
but I just can't figure out where to start.
Answer
Hints :
Show that it is a decreasing sequence bounded below.
Notice that a0=x, and ak=f(ak−1) where f(y)=xy. By (1), we know that L=limak exists. Now
ak→L⇒f(ak)→f(L)
since f is continuous. However, f(ak)=ak+1, and so the the sequences {f(ak)} and {ak} are actually the same sequence. Since a sequence cannot converge to two different points,
L=f(L)=xL
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