Simple Convergence / Divergence Calc 2

In summary, the problem is to determine the convergence or divergence of the series Summation n=1 to Infinity of 1/sqrt(n^3 + 2n). The conversation discusses the use of comparison and integral tests, with the conclusion that the comparison test is the best approach since 1/sqrt(n^3 + 2n) is always smaller than 1/n^(3/2).
  • #1
Alex G
24
0

Homework Statement



I have stared at this too long and do not know which test to approach it with, even writing it out. The problem is
State the Convergence or Divergence of the given series:

Summation n=1 to Infinity of 1 / sqrt (n^3 + 2n)

Homework Equations


I narrowed it down to possibly a comparison test, I can't really see an integral test coming in.
I know the answer in the back of the book says convergence
 
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  • #2
Comparison test works well here since sqrt (n^3 + 2n) > n^3/2. The later being a p series with p >1.

Integral test would be hard to use directly without any approximations which can be done with the comparison test.
 
  • #3
I thought the same, however, as I calculate out different and higher successive numbers for
1 / sqrt(n^3 + 2n), it's always smaller than 1 / n^(3/2) :(
 
  • #4
Alex G said:
I thought the same, however, as I calculate out different and higher successive numbers for
1 / sqrt(n^3 + 2n), it's always smaller than 1 / n^(3/2) :(

If you want to prove convergence, isn't 1/sqrt(n^3+2n)<1/n^(3/2) the condition you want?
 
  • #5
Alex G said:
I thought the same, however, as I calculate out different and higher successive numbers for
1 / sqrt(n^3 + 2n), it's always smaller than 1 / n^(3/2) :(

That's precisely what you want... ;)
 
  • #6
/sigh I'm sorry, this is my 6th chapter review section ... I think I'm going to quit while ahead haha, thank you!
 

Related to Simple Convergence / Divergence Calc 2

1. What is Simple Convergence/Divergence in Calculus 2?

In Calculus 2, Simple Convergence/Divergence refers to the behavior of a series, which is a sum of an infinite sequence of numbers. A series is said to be convergent if the sum of its terms approaches a finite number as the number of terms increases. On the other hand, a series is divergent if the sum of its terms does not approach a finite number.

2. How is Simple Convergence/Divergence determined?

Simple Convergence/Divergence can be determined using various tests, such as the comparison test, ratio test, and integral test. These tests help determine the behavior of a series and whether it is convergent or divergent.

3. What is the importance of Simple Convergence/Divergence in Calculus 2?

Simple Convergence/Divergence is important in Calculus 2 as it helps determine the behavior and convergence of a series. This information is crucial in solving various mathematical problems and applications, such as finding areas under curves and calculating probabilities.

4. Can a series be both convergent and divergent?

No, a series cannot be both convergent and divergent. A series can only have one of these two behaviors. However, there are cases where a series may not be classified as either convergent or divergent, and in such cases, further testing may be required to determine its behavior.

5. How does Simple Convergence/Divergence relate to other concepts in Calculus 2?

Simple Convergence/Divergence is closely related to other concepts in Calculus 2, such as limits, derivatives, and integrals. These concepts help determine the behavior of a series and can be used to prove the convergence or divergence of a series. Additionally, the techniques used in Simple Convergence/Divergence, such as the comparison and ratio tests, are also used in other areas of Calculus 2, such as infinite series and improper integrals.

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