Determine this sequence increasing or decreasing

In summary, the sequence an is defined recursively as a1 = 1 and an+1 = 1/(2+an) for all n≥1. The speaker plans to prove the sequence is convergent using the monotone sequence theorem, but is struggling to determine if it is increasing or decreasing. They suggest using the difference between consecutive terms, an+1-an, and factoring to determine the monotonicity. They also mention finding the value of an where the sequence would be stationary.
  • #1
e179285
24
0
A sequence (an) is recursively defined by a1 = 1 and
an+1 =1 /(2+an ) for all n≥1

I'll prove this sequence is convergent by monoton sequence theorem.ı can find ıt is bounded but ı cannot decide it is monoton because when ı write its terms,Its terms are increasing sometimes decreasing sometimes.

How can ı prove it is increasing or decreasing?
 
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  • #2
e179285 said:
How can ı prove it is increasing or decreasing?

For what value of an would it be stationary, ie. an+1 = an?
 
  • #3
Do an+1-an and you'll have to combine it into one fraction and then do some factoring and you'll see if it's decreasing or increasing.
 

Related to Determine this sequence increasing or decreasing

1. What is the definition of a sequence?

A sequence is a list of numbers that follow a specific pattern or rule.

2. How can I determine if a sequence is increasing or decreasing?

A sequence is increasing if each number in the list is greater than the one before it. A sequence is decreasing if each number in the list is less than the one before it.

3. Can a sequence be both increasing and decreasing?

No, a sequence can only be either increasing or decreasing. If a sequence has alternating increasing and decreasing terms, it is considered neither increasing nor decreasing.

4. What are some common patterns in increasing and decreasing sequences?

Some common patterns in increasing sequences include linear growth (adding a constant number to each term) and exponential growth (multiplying by a constant number each time). For decreasing sequences, common patterns include linear decay (subtracting a constant number from each term) and exponential decay (dividing by a constant number each time).

5. Why is it important to determine if a sequence is increasing or decreasing?

Determining if a sequence is increasing or decreasing can help identify patterns and predict future terms in the sequence. It can also be useful in various fields such as mathematics, science, and economics where understanding and analyzing patterns is crucial.

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