Show whether a funtion converges

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In summary, the question is asking whether the series from k = 1 to infinity of 1/(k+6) converges. The answer provided states that it diverges, but the person is confused because the limit of the function approaches zero and it makes sense according to the p-test. However, the question is not asking about the limit, but rather the convergence of the series. Various convergence tests are suggested to help solve the problem. The person eventually discovers the answer using the p-test, but is still confused about how the sum can converge to a non-zero value when zero is being added. The conversation ends with an example showing how adding zero to a series does not necessarily make it converge to zero.
  • #1
Gott_ist_tot
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I have a homework problem to show whether a funtion converges.

the sum from k =1 to infinity of 1/(k+6)
The answer says that it diverges although I do not understand this. Doesn't the limit approach zero? It makes sense due to the p-test where p = 1. But t should approach zero. thanks for any help.
 
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  • #2
The question is asking if

[tex]\sum_{k=1}^{+\infty} \frac{1}{k+6}[/tex]

converges, not if

[tex]\lim_{k \rightarrow +\infty} \frac{1}{k+6}[/tex]

converges.
 
  • #3
Try some of the convergence tests that you know.

You can try the ratio test, direct comparison, the limit comparison test, etc...

Give us some attempts and we'll see if we can help you out.
 
  • #4
Yeah, I got the answer with the p test. I will look over the proof really well. I just don't grasp how you can effectively be adding zero to the sum and it does not converge to zero also. I just know that it does.
 
  • #5
You could be actually adding 0 to the sum, and still not have it converge to zero. e.g. 1 + 0 + 0 + 0 + 0 + ... = 1
 

FAQ: Show whether a funtion converges

What is the definition of convergence in a function?

Convergence in a function refers to the behavior of the function as the input values approach a specific value or infinity. It means that as the input values get closer and closer to a certain value, the output values of the function also get closer and closer to a specific value.

How do you determine if a function converges?

In order to determine if a function converges, you can use different methods such as the limit definition, the ratio test, the root test, or the comparison test. These methods involve evaluating the behavior of the function as the input values approach a certain value or infinity.

Can a function converge to multiple values?

No, a function can only converge to one specific value or infinity. If a function has multiple limit points, it is considered to be divergent and does not converge.

What is the significance of a function converging?

The convergence of a function is important as it helps us understand the behavior of the function and make predictions about its values. It also allows us to determine the domain and range of the function and analyze its properties.

Is it possible for a function to not converge?

Yes, it is possible for a function to not converge. This typically occurs when the function has oscillating behavior or when the limit of the function does not exist. In these cases, the function is considered to be divergent and does not converge to a specific value.

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