Determine the interval of convergence for

In summary, the interval of convergence refers to the range of values for which a given series will converge. This can be determined using tests such as the ratio test, root test, or alternating series test, which help find the radius of convergence. The radius of convergence is the distance between the center of the series and the point where it converges and is crucial in determining the interval of convergence. It is important to determine the interval of convergence as it helps understand the behavior of the series. If a series does not have a finite interval of convergence, more advanced techniques such as power series or Laurent series must be used to determine its behavior.
  • #1
Jamin2112
986
12

Homework Statement



[n=0 to ∞] ∑x2n/n!

Homework Equations



The ratio test

The Attempt at a Solution



So, here is the ratio of of the (n+1)th term to the nth term:

| [x2(n+1)/(n+1)!] / [x2n/n!] | =

| [x2nx2/(n+1)!] * [n!/x2n] | =

| x2/n |, which will be will be less than one when n is big enough.

So this converges for all x, right?
 
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  • #2
Correct.
 

What is the interval of convergence?

The interval of convergence is the range of values for which a given series will converge, meaning that the sum of its terms will approach a finite value as the number of terms increases.

How do you determine the interval of convergence?

To determine the interval of convergence, you can use tests such as the ratio test, root test, or alternating series test. These tests help determine the radius of convergence, which is the distance between the center of the series and the point where the series converges. The interval of convergence will then be the range of values within this radius.

What is the radius of convergence?

The radius of convergence is the distance between the center of the series and the point where the series converges. It is a crucial value in determining the interval of convergence, as it helps identify the range of values for which the series will converge.

Why is it important to determine the interval of convergence?

Determining the interval of convergence is essential because it helps us understand the behavior of a given series. It tells us the range of values for which the series will converge and whether the series will diverge for values outside of this interval.

What happens if a series does not have a finite interval of convergence?

If a series does not have a finite interval of convergence, it means that the series will either diverge for all values or converge for all values. In such cases, it is necessary to use more advanced techniques, such as power series or Laurent series, to determine the behavior of the series.

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