Does this Series Converge or Diverge, by which test(s)?

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Homework Statement



Does The series Ʃ (2n)!/(n-1)*3^n converge or diverge?

(Starts at n=2 to infinity )

Homework Equations





The Attempt at a Solution



I tried the ratio test and nth-term test, and ended up with infinity, I'm not sure about it's convergence.
 
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Alexc475 said:

Homework Statement



Does The series Ʃ (2n)!/(n-1)*3^n converge or diverge?

(Starts at n=2 to infinity )

Homework Equations





The Attempt at a Solution



I tried the ratio test and nth-term test, and ended up with infinity, I'm not sure about it's convergence.

If the ratio you get from the ratio test goes to infinity, then the series diverges.
 
Dick said:
If the ratio you get from the ratio test goes to infinity, then the series diverges.

Ohh no wonder. Thank you! I forgot that if L>1 (L being the limit) that it converges
 
Alexc475 said:
Ohh no wonder. Thank you! I forgot that if L>1 (L being the limit) that it converges
No, if L > 1, it diverges.
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...

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