Using ε,δ-Definition to Show $\lim_{x\to a}\frac{1}{x}=\frac{1}{a}$

  • Thread starter Thread starter wonnabewith
  • Start date Start date
wonnabewith
Messages
4
Reaction score
0

Homework Statement


The question is asking to use the ε, δ-definition of limit to show that lim x->a 1/x=1/a


Homework Equations


<br /> \lim_{x \to a} f(x) = L<br />

The Attempt at a Solution


Here is what I have so far:
|1/x-x/a|<ε
and |x-a|<δ
I have no idea what to do next, please help
thanx
 
Physics news on Phys.org


This guy does a good job explaining it.
 
Last edited by a moderator:
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...
Back
Top