Limits: Finding the Value of (x - Sinx) / x^3

  • Thread starter Thread starter rambo5330
  • Start date Start date
  • Tags Tags
    Limits Value
rambo5330
Messages
83
Reaction score
0

Homework Statement


lim (x->0) of (x - Sinx) / x^3


Homework Equations





The Attempt at a Solution


I would like to know the proper route for analyzing that question... the text is saying i should end up with 1/6 ...however I'm not sure how they arrived at that answer ...
 
Physics news on Phys.org
Are you familiar with l'hopitale's rule?

if lim (x->0) a/b = 0/0 or infinity/infitity then lim (x->0) a/b = lim (x->0) a'/b'
 
not familiar with that yet ...
 
Another approach is to replace sin x by a few terms of its Maclaurin series, but if you don't know L'Hopital's Rule, you probably don't know anything about series yet, either. Short of those two techniques, I can't think of anything else that would work for you.
 
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...

Similar threads

Replies
19
Views
2K
Replies
5
Views
1K
Replies
12
Views
2K
Replies
5
Views
2K
Replies
13
Views
3K
Replies
11
Views
3K
Replies
8
Views
1K
Replies
8
Views
2K
Back
Top