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

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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
 
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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