Finding the Limit of a Series: [a1]=√12, [an+1]=√(12+an)

In summary, the given series converges to a limit, L, which can be solved for using the equation a_n = √(12+a_(n+1)). The limit is the same for both a_n and a_(n+1).
  • #1
jaqueh
57
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Homework Statement


What does the series converge to?
[a1]=√12
[an+1]=√(12+an)


Homework Equations


Let L = the limit it approaches


The Attempt at a Solution


I don't know if i did this correctly but I made
L = √(12+√(12+√(12+...)))
then L2 = 12+√(12+√(12+...))
then L = 12 + 12∞-1...12
thus L = ∞√(12 + 12∞-1...12)
 

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  • #2
If it converges then a_n approaches L as n->infinity. So does a_(n+1). Put that into a_n=sqrt(12+a_(n+1)).
 
  • #3
Dick said:
If it converges then a_n approaches L as n->infinity. So does a_(n+1). Put that into a_n=sqrt(12+a_(n+1)).

ok i get that an+1 converges now because it is in the an series, but what is the limit that it approaches?
 
  • #4
jaqueh said:
ok i get that an+1 converges now because it is in the an series, but what is the limit that it approaches?

It approaches the same limit as a_n, call it L. Solve for L!
 

FAQ: Finding the Limit of a Series: [a1]=√12, [an+1]=√(12+an)

What is the formula for finding the limit of a series?

The formula for finding the limit of a series is as follows:
lim n→∞ an = L, where L is the limit of the series and n is the number of terms in the series. This means that as the number of terms in the series increases, the value of the terms will approach the limit value.

How can I apply the formula to the given series [a1]=√12, [an+1]=√(12+an)?

To apply the formula, you first need to find the value of a1 which is given as √12. Then, use this value to find the value of a2 which is √(12+√12). Continue this process and as n approaches infinity, the value of the terms will approach the limit value.

Can you provide an example of finding the limit of a series using this formula?

Yes, for example, let's say we have a series [a1]=1, [an+1]= 1/(an+1). To find the limit, we can plug in the values of the terms into the formula:
lim n→∞ an = 1/(1+1) = 1/2. This means that as n approaches infinity, the value of the terms will approach 1/2.

Are there any specific conditions for using this formula to find the limit of a series?

Yes, the series must be infinite and the terms must follow a specific pattern. In this case, the terms are dependent on the previous term, as shown in the formula [an+1]=√(12+an). Additionally, the series must converge, meaning that the terms must approach a finite limit value as n approaches infinity.

What is the importance of finding the limit of a series in science?

Finding the limit of a series is important in science because it can help us understand the behavior and trends of certain phenomena. For example, in physics, finding the limit of a series can help us predict the behavior of a system as it approaches infinity. In other fields such as chemistry and biology, finding the limit of a series can help us understand the trends and patterns in data, which can lead to new discoveries and advancements.

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