Analysis of "X = (xn) Sequence of Strictly Positive Real Numbers

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In summary, the conversation discusses a sequence of positive real numbers, (xn), with a limit of (x(n+1)/xn) < 1. It is shown that for some r between 0 and 1, and some constant C, xn < Cr^n for all sufficiently large natural numbers n. It is also proven that the limit of xn is 0. To show xn < Cr^n, it is suggested to use induction and apply an inequality involving xk+n and xk.
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buzzmath
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X = (xn) is a sequence of strictly positive real numbers, where (xn) is x subscript n, such that lim(x(n+1)/xn) < 1. Show that for some r with 0<r<1 and some C>0 that 0<xn<Cr^n for all sufficiently large natural numbers n. and that lim(xn) = 0

So for I have this:
choose r such that lim(x(n+1)/xn)<r<1 and take a neighborhood of this limit to be the interval (-1,r) So there exists a natural number K such that 0<x(n+1)/xn<r for all n>=K. I can also write r = 1/(1+a) where a>0 and show that lim(r^n)=0. All I need to show now is that xn<Cr^n. Because I know that if lim(r^n)=0 and ||xn - 0||<=C|r^n| where C>0 then lim(r^n)=0. I'm not really sure how to get the xn<Cr^n though. Any help or suggestions?
 
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You've shown xn+1/xn<r for n>=K. You can rewrite this as xn+1<r*xn. Apply induction to get an inequality involving xk+n and xk.
 

FAQ: Analysis of "X = (xn) Sequence of Strictly Positive Real Numbers

What is the purpose of analyzing the sequence (xn) of strictly positive real numbers?

The purpose of analyzing this sequence is to better understand its behavior and patterns, and to potentially make predictions about its future values. This type of analysis is commonly used in fields such as mathematics, physics, and economics.

How is the limit of the sequence (xn) determined?

The limit of the sequence (xn) is determined by finding the value that the terms of the sequence approach as n (the number of terms) approaches infinity. This can be done through various methods, such as finding the average of the terms or using mathematical formulas.

What is the difference between convergence and divergence in the analysis of (xn)?

In the context of analyzing the sequence (xn), convergence refers to the situation where the limit of the sequence exists and is a specific value, while divergence refers to the situation where the limit does not exist or is infinity. Convergence indicates that the terms of the sequence are approaching a fixed value, while divergence indicates that the terms are not approaching a specific value.

What are some applications of analyzing the (xn) sequence of strictly positive real numbers?

The analysis of this sequence has many practical applications, including predicting stock market trends, modeling population growth, and understanding the behavior of complex systems. It can also be used in computer algorithms and data analysis to identify patterns and make predictions.

Can the (xn) sequence of strictly positive real numbers have multiple limits?

No, the (xn) sequence can only have one limit. However, it is possible for the limit to be infinity or for the sequence to not have a limit at all, in which case it is considered divergent.

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