Convergent Series: Find Sequence of Positive Reals

In summary, a convergent series is a sequence of numbers that approaches a finite limit as more terms are added. To find the sequence of positive real numbers for a convergent series, a formula for the general term of the series can be used. Negative terms cannot be present in a convergent series as it would cause the series to diverge. There are various tests that can be used to determine if a series is convergent or divergent, such as the ratio test and the comparison test. Convergent series have a wide range of applications in fields such as mathematics, physics, and engineering for calculating values, approximating areas, and making predictions.
  • #1
rainwyz0706
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Homework Statement



Find a sequence (an) of positive real numbers such the sum of an from 1 to infinity is convergent but the number of k such that a(k+1)>ak divided by n tends to 1 as n tends to infinity.

Homework Equations





The Attempt at a Solution


I don't have a clue how to find a sequence here. Could anyone please give a hint? Any help is appreciated!
 
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  • #2
Be creative. Take a nice convergent decreasing series like 1/2^n. Now think about ways of rearranging the terms.
 

FAQ: Convergent Series: Find Sequence of Positive Reals

1. What is a convergent series?

A convergent series is a sequence of numbers that approaches a finite limit as the number of terms increases. This means that the sum of the terms in the series gets closer and closer to a specific value as more terms are added.

2. How do you find the sequence of positive real numbers for a convergent series?

To find the sequence of positive real numbers for a convergent series, you can use the formula for the general term of the series. This formula will give you a pattern to follow for finding the individual terms of the sequence.

3. Can a convergent series have negative terms?

No, a convergent series cannot have negative terms. This is because a negative term would cause the sum of the series to become smaller as more terms are added, making it diverge rather than converge.

4. How can you determine if a series is convergent or divergent?

There are several tests that can be used to determine if a series is convergent or divergent, such as the ratio test, the comparison test, and the integral test. These tests involve analyzing the behavior of the terms in the series and can help determine if the series will approach a finite limit or not.

5. What are some real-world applications of convergent series?

Convergent series are used in many scientific and mathematical applications, such as calculating the value of pi, approximating the area under a curve, and predicting population growth. They are also commonly used in physics and engineering to model real-world systems and make accurate predictions.

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