Monotonic Sequence Theorem Question

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The discussion centers on the Monotonic Sequence Theorem, confirming that a decreasing sequence bounded between 5 and 8 has a limit. It is established that the limit exists due to the sequence being both bounded and monotonic. However, it is clarified that while the limit is at least 5, it cannot be definitively stated that the limit is exactly 5 unless 5 is the infimum of the sequence. The importance of distinguishing between a lower bound and the infimum is emphasized. Thus, the limit of the sequence is not necessarily 5 but is at least 5.
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Suppose you know that \left{ a_n \right} is a decreasing sequence and all its
terms lie between the numbers 5 and 8. Explain why the sequence has a limit. What can
you say about the value of the limit?

My Answer:

This sequence has a limit because it is both bounded and monotonic, as it is stated in the
Monotonic Sequence Theorem. The minimum value of this particular limit must be 5.

My question:

Is that thoroughly answered? Did I miss anything?
 
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thiago_j said:
Suppose you know that \left{ a_n \right} is a decreasing sequence and all its
terms lie between the numbers 5 and 8. Explain why the sequence has a limit. What can
you say about the value of the limit?

My Answer:

This sequence has a limit because it is both bounded and monotonic, as it is stated in the
Monotonic Sequence Theorem. The minimum value of this particular limit must be 5.

My question:

Is that thoroughly answered? Did I miss anything?

Well, you can say that the limit is greater than or equal to five. As you know, a certain theorem says that any bounded, monotonic sequence has a limit. But if the problem is stated as you have written it, I don't think you can say that the limit must be 5.

All of the terms lie between 5 and 8. But do you know if the infimum of the sequence is 5? If the infimum is 5, then yes, the limit is also 5. But if 5 is simply a lower bound (and not necessarily the infimum), then you can't say that the limit is 5.
 
I think get it. The limit is not necessarily 5.

Thanks.
 
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