Series with divergence: Quick easy question

In summary, the conversation is about finding the interval of convergence for the given function, which is found to be (1,infinity). The issue is with determining the interval of divergence, which some people argued to be (1,infinity) while others said it was (-infinity, 1]. The person is unsure and asks for clarification. Another person suggests using the integral test to find the interval of divergence, and they walk through the steps of integrating the function. In the end, the person realizes their initial answer was correct.
  • #1
MitsuShai
159
0

Homework Statement



http://i324.photobucket.com/albums/k327/ProtoGirlEXE/q8.jpg

Attempt to the solution:
ok I got that it only converges on (1,infinity) because I solved it and q>1 is where it only converges, so for the rest it diverges.
But I'm having trouble with putting the divergency in interval notation because some people where saying it was divergent on (1, infinity) and I typed that in and got it wrong

and I typed in [0,1] on accident and without thinking

but now I'm thinking it's divergent from (-infinity, 1], am I right?
 
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  • #2
Have you tried to use the integral test? You integrate:
[tex]
\int\frac{dx}{x(\ln x)^{q}}
[/tex]
 
  • #3
hunt_mat said:
Have you tried to use the integral test? You integrate:
[tex]
\int\frac{dx}{x(\ln x)^{q}}
[/tex]

yeah u=lnx du=1/x
= u^(-q+1)= (ln x)^(1-q)/(1-q)
 
  • #4
hunt_mat said:
Have you tried to use the integral test? You integrate:
[tex]
\int\frac{dx}{x(\ln x)^{q}}
[/tex]


Could you explain why I have to do the integral test to find what integral it diverges?
 
  • #5
nevermind my answer was right.
 

FAQ: Series with divergence: Quick easy question

1. What is a series with divergence?

A series with divergence is a type of mathematical series where the terms do not approach a finite limit as the number of terms increases. This means that the series does not have a sum or a finite value.

2. How can you tell if a series has divergence?

One way to tell if a series has divergence is to use the divergence test, which states that if the limit of the terms in a series does not equal 0, then the series diverges.

3. Can a series with divergence still have a partial sum?

Yes, a series with divergence can still have a partial sum, but it will not have a finite value. The partial sum will continue to increase as more terms are added, but it will not approach a specific value.

4. Are there any real-world applications for series with divergence?

Series with divergence are often used in physics and engineering to model systems with infinite energy or constantly increasing quantities, such as radioactive decay or population growth.

5. How can series with divergence be evaluated?

Series with divergence cannot be evaluated in the traditional sense, as they do not have a finite sum. However, they can still be studied and analyzed using various mathematical techniques, such as the comparison test or the ratio test.

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