Limits of Sin(n)/n: Solving for N

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Homework Help Overview

The discussion revolves around evaluating the limit of sin(n)/n as n approaches infinity, specifically using the definition of limits without additional theorems. The original poster expresses uncertainty about manipulating the sine function within the limit and how to establish a suitable N for the epsilon definition.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • Participants discuss the possibility of using geometric arguments and clarify the bounds of the sine function. There is a focus on understanding how to handle the absolute value in the limit definition.

Discussion Status

The conversation is ongoing, with some participants providing supportive comments and clarifications regarding the properties of the sine function. There is no explicit consensus, but guidance has been offered regarding the approach to take.

Contextual Notes

There is a mention of constraints related to the use of the definition of limits and the original poster's concern about the absolute value affecting their reasoning. The limit is specifically noted to be as n approaches infinity.

mjjoga
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lim (sin⁡(n)/n)=0.
The instruction say I can only use the definition of limit and no additional theorems.
So the first thing I should do is figure out if l sin(n)/n l < epsilon, find out what n is greater than. I can pull the 1/n out of the absolute value, but I don't know how to get the sine out. I mean, I know that sin(anything) would be less than say 2, but I don't know if I can do that step with the absolute value still there. Once I can define N>... I can do the rest of it.
Thanks for any help,
mjjoga
 
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Are you allowed to use geometric arguments? If you are, that is actually the best approach here.
 
welcome to pf!

hi mjjoga! welcome to pf! :smile:
mjjoga said:
lim (sin⁡(n)/n)=0.

I know that sin(anything) would be less than say 2

(i assume that's the limit as n -> ∞ ?)

well, sin(anything) is ≤ 1, isn't it? :wink:

yes, if you use that the proof should be easy :smile:
 


tiny-tim said:
hi mjjoga! welcome to pf! :smile:


(i assume that's the limit as n -> ∞ ?)

well, sin(anything) is ≤ 1, isn't it? :wink:

yes, if you use that the proof should be easy :smile:


Oh, it's to infinity...

I thought it was to 0. My bad, ignore my post!
 
he he :biggrin:
 
Yes, it is to infinity, my book wrote it just like that though, it's weird. I was just worried about the abs. value messing it up, but even with it it will be less than or equal to 1. Thanks guys, I appreciate it.
mjjoga
 

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