Applying Integral Test: Why did they integrate from 1 to ∞ instead of

In summary, integrating from 1 to ∞ allows us to determine the convergence or divergence of a series by capturing the function's behavior as x approaches infinity. A different lower limit can sometimes be used with the Integral Test, but 1 is often the most convenient. The Integral Test can be applied to positive, continuous, and decreasing series, and the Cauchy Condensation Test shows the relationship between the integral's value and the series' convergence. However, the Integral Test cannot be used for all types of series and other tests must be utilized for alternating or negative series.
  • #1
InvalidID
84
3
Consider example 4 in the attachment.

Why did they integrate from 1 to ∞ instead of e to ∞?
 

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  • #2
InvalidID said:
Consider example 4 in the attachment.

Why did they integrate from 1 to ∞ instead of e to ∞?
Your textbook must have a theorem in which they present the integral test. Find it and see what it says.
 

Related to Applying Integral Test: Why did they integrate from 1 to ∞ instead of

1. Why did they integrate from 1 to ∞ instead of using a finite upper limit?

Integrating from 1 to ∞ allows us to capture the behavior of the function as x approaches infinity. This is important because it helps us determine if the series converges or diverges.

2. Can we use a different lower limit instead of 1 when applying the Integral Test?

Yes, in some cases, a different lower limit can be used. However, 1 is often the most convenient lower limit to use because it simplifies the calculations and allows us to easily compare the series with the p-series test.

3. How do we know when to use the Integral Test?

The Integral Test can be used when the series is positive, continuous, and decreasing. If these conditions are met, then we can use the Integral Test to determine the convergence or divergence of the series.

4. What is the relationship between the value of the integral and the convergence of the series?

If the integral of the function from 1 to ∞ converges, then the series also converges. If the integral diverges, then the series also diverges. This is known as the Cauchy Condensation Test.

5. Can the Integral Test be used for all types of series?

No, the Integral Test can only be used for series with positive terms. It cannot be used for alternating series or series with negative terms. In those cases, other tests such as the Alternating Series Test or the Comparison Test should be used instead.

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