Convergence Test: Solving Homework on (n!)/(2n)!

In summary, the conversation is discussing how to solve a series using either the Root Test or the Ratio Test. The person is struggling with breaking up the (2n)! term to cancel with (n!) and requests hints. The other person suggests using the ratio test and the issue is resolved.
  • #1
lmannoia
32
0

Homework Statement


It's from sum (n=1, to infinity.. I apologize for not knowing how to type it in properly!) of (n!)/(2n)!


Homework Equations





The Attempt at a Solution


We're supposed to use either the Root Test or the Ratio Test to determine if the series converges or not. My problem is that I don't know how to break up (2n!) so that it'll cancel with (n!). Any hints are appreciated. Thank you!
 
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  • #2
If you use the ratio test, you shouldn't have to worry too much about breaking up the (2n)! term.
 
  • #3
Hint: when you see factorials, always try the ratio test.
 
  • #4
Looking at it again, I figured it out. Thanks for the hint, too!
 

Related to Convergence Test: Solving Homework on (n!)/(2n)!

1. What is a convergence test?

A convergence test is a mathematical method used to determine whether a series or sequence of numbers approaches a finite limit or continues to increase without bound. It is used to check the convergence or divergence of a series, which is important in determining the convergence of integrals and the accuracy of numerical approximations.

2. How do I use the ratio test to solve (n!)/(2n)?

The ratio test is a common convergence test used to determine the convergence or divergence of a series. To use the ratio test on (n!)/(2n), you would first take the limit as n approaches infinity of |(an+1) / (an)|. If the resulting limit is less than 1, the series converges. If it is greater than 1, the series diverges. If the limit is equal to 1, the test is inconclusive and other methods may need to be used.

3. Can I use the root test to solve (n!)/(2n)?

Yes, the root test is another commonly used convergence test that can also be applied to (n!)/(2n). To use the root test, take the limit as n approaches infinity of the nth root of |an|. If the resulting limit is less than 1, the series converges. If it is greater than 1, the series diverges. If the limit is equal to 1, the test is inconclusive and other methods may need to be used.

4. What is the difference between absolute and conditional convergence?

Absolute convergence refers to the convergence of a series regardless of the order of the terms, while conditional convergence only applies when the terms of a series are arranged in a specific order. For example, the series (-1)n / n converges absolutely, but only conditionally when the terms are arranged from largest to smallest.

5. What other convergence tests can I use to solve (n!)/(2n)?

In addition to the ratio and root tests, there are several other convergence tests that can be used to solve (n!)/(2n). These include the integral test, comparison test, alternating series test, and the limit comparison test. It is important to choose the most appropriate test for the series at hand, as different tests may yield different results.

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