Proving Convergence of {S_n/n} for Bounded Sequence {S_n}

In summary: Yes it does! Check the squeeze theorem carefully!The squeeze theorem states that if {S_n} is a bounded sequence and {L} is a limit, then {S_n/n} is convergent.
  • #1
Shayes
12
0

Homework Statement



If {S_n} is a sequence whose values lie inside an interval [a,b], prove {S_n/n} is convergent.

We don't know Cauchy sequence yet. All we know is the definition of a bounded sequence, and convergence and divergence of sequences. Along with comparison tests and Squeeze theorem.

Homework Equations



Limit of a sequence: abs(S_n - L) < Epsilon whenever n>=N, provided for Epsilon>0.

The Attempt at a Solution



I see that every convergent sequence is bounded, but the opposite isn't always true, so how do I show that the smaller sequence is convergent given that {S_n} is bounded?
 
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  • #2


I think you can use the squeeze theorem, since a/n <= S_n/n <= b/n and they both converge to 0. Do you need to proove that a/n converges or can you use that?
 
  • #3


susskind_leon said:
I think you can use the squeeze theorem, since a/n <= S_n/n <= b/n and they both converge to 0. Do you need to proove that a/n converges or can you use that?

i thought of that, but is that the same as saying the entire sequence converges?

i feel like this statement says that each term is squeezed between the interval, but it doesn't say anything about if the limit of the sequence's terms is taken to infinity.
 
  • #4


Yes it does! Check the squeeze theorem carefully!
 
  • #5


Shayes said:
i thought of that, but is that the same as saying the entire sequence converges?

i feel like this statement says that each term is squeezed between the interval
I have no idea what this means, but the crucial point is the "n" in the denominator. What are the linits of a/n and b/n?

, but it doesn't say anything about if the limit of the sequence's terms is taken to infinity.
 

1. How do you prove the convergence of a bounded sequence?

To prove the convergence of a bounded sequence, you must show that the sequence is both bounded and monotonic. This can be done through various methods such as the squeeze theorem, the ratio test, or the root test.

2. What is the importance of proving convergence for a bounded sequence?

Proving convergence for a bounded sequence is important because it allows us to determine the behavior of the sequence as it approaches its limit. This can help us understand the long-term behavior of a system or function.

3. Can a bounded sequence still converge if it is not monotonic?

Yes, a bounded sequence can still converge if it is not monotonic. However, in order to prove convergence, you must use a different method such as the Bolzano-Weierstrass theorem or the Cauchy criterion.

4. Is proving convergence of a bounded sequence always necessary?

Not always. In some cases, it may be sufficient to show that the sequence is bounded and has a limit point. However, proving convergence is a more rigorous way to determine the behavior of the sequence.

5. What implications does the convergence of a bounded sequence have on its limit?

If a bounded sequence is proven to converge, then its limit is unique and can be used to make predictions about the behavior of the sequence. This can be helpful in various fields such as finance, physics, and engineering.

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