Determine convergence of series using integral test

In summary, the integral test is a method used to determine the convergence or divergence of a series by comparing it to an integral. To use the integral test, you must first take the integral of the series and evaluate it to see if it is convergent or divergent. The conditions for using the integral test include having positive terms that decrease monotonically and being able to evaluate the integral using standard integration techniques. The integral test can be used to determine both absolute and conditional convergence, but it has limitations such as not being applicable to series with alternating signs or terms that do not decrease monotonically.
  • #1
lha08
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Homework Statement


How can i find if the following series is convergent or divergent using the INTEGRAL TEST?
sigma (n=1 to infinity)= n/(n^4+1)


Homework Equations





The Attempt at a Solution


The answer says that the initial step involves changing it to: 1/2(2x)/(1+(x^2)^2)..but why is that?
 
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  • #2
Hi lha08! :smile:

(try using the X2 tag just above the Reply box :wink:)
lha08 said:
sigma (n=1 to infinity)= n/(n^4+1)

The answer says that the initial step involves changing it to: 1/2(2x)/(1+(x^2)^2)..but why is that?

Because ∫dy/(1 + y2) is easy. :wink:
 

What is the integral test?

The integral test is a method used to determine the convergence or divergence of a series by comparing it to an integral. It states that if the integral of the series is convergent, then the series itself is also convergent. Conversely, if the integral is divergent, then the series is also divergent.

How do you use the integral test to determine convergence?

To use the integral test, you must first take the integral of the series. Then, evaluate the integral to see if it is convergent or divergent. If the integral is convergent, then the series is also convergent. If the integral is divergent, then the series is also divergent.

What are the conditions for using the integral test?

The integral test can only be used for series with positive terms that decrease monotonically (i.e. always decreasing or always increasing). Additionally, the integral must be able to be evaluated using standard integration techniques.

Can the integral test be used to determine absolute convergence?

Yes, the integral test can be used to determine both absolute and conditional convergence. If the integral of the series is convergent, then the series is absolutely convergent. However, if the integral is convergent but the series is not, then the series is conditionally convergent.

What are the limitations of the integral test?

The integral test can only be used for series with positive terms that decrease monotonically. It also cannot be used for series with alternating signs or series with terms that do not decrease monotonically. Additionally, the integral must be able to be evaluated using standard integration techniques.

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