- #1
A.MHF
- 26
- 1
Hi everyone, I'm currently taking Calc II course and I'm kind of stuck in this ratio test proof thing.
http://blogs.ubc.ca/infiniteseriesmodule/appendices/proof-of-the-ratio-test/proof-of-the-ratio-test/
I'm trying to understand the proof, but there are some parts that I don't really get.
So assuming that |an+1/an| = L < 1
and that L < r
|an+1/an| < r
but then, the proof says there is an integer N which is < or = to n. From where did that come from? Why do we need it in the first place? And how does it relate to the proof?
The proof goes on and I don't really have any idea what's going on.
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I tried making a number line to understand what's going on but this seems so subtle.
Homework Statement
http://blogs.ubc.ca/infiniteseriesmodule/appendices/proof-of-the-ratio-test/proof-of-the-ratio-test/
I'm trying to understand the proof, but there are some parts that I don't really get.
So assuming that |an+1/an| = L < 1
and that L < r
|an+1/an| < r
but then, the proof says there is an integer N which is < or = to n. From where did that come from? Why do we need it in the first place? And how does it relate to the proof?
The proof goes on and I don't really have any idea what's going on.
Homework Equations
-
The Attempt at a Solution
I tried making a number line to understand what's going on but this seems so subtle.