What Are Ratio Test Examples and How Do Notations Affect Cancellations?

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Homework Statement



I'm attached a pic of an example.

just wondering when i was trying the ratio test with a problem, i noticed numbers displayed in the pic.

is another way to write those examples like this: 5*5 or (x-1)*(x-1) ?

is that all the n+1 means?

also if there was something like: (n^7) / (n+1)^7 how can those cancel?
sorry about notation there.

thanks

Homework Equations





The Attempt at a Solution

 
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nevermind.
 
\frac{n^7}{(n+1)^7} behaves like \frac{n^7}{n^7} for large n

so in your example it's just 1 if the limit goes to infinity. Can you see it?
 
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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