How can I use this hint to help prove the limit using the definition?

  • Thread starter Thread starter scientifico
  • Start date Start date
  • Tags Tags
    Definition Limit
scientifico
Messages
181
Reaction score
0

Homework Statement


Hello, I have to prove, using the limit definition, that \lim_{x\to 1^{+}}{\frac{x-3}{x-1}}=-\infty


The Attempt at a Solution


I've set this unequation \frac{x-3}{x-1} < - M but it doesn't lead to the result 1<x<1+\frac{2}{M+1}, what did I wrong ?

Thanks
 
Physics news on Phys.org
You do understand that we can't tell you what you did wrong if you don't tell us what you did, don't you?
 
I've set up this unequation \frac{x-3}{x-1} < - M to prove the limit using its definition but it doesn't lead to the result 1<x<1+\frac{2}{M+1}
 
scientifico said:
I've set up this unequation \frac{x-3}{x-1} < - M to prove the limit using its definition but it doesn't lead to the result 1<x<1+\frac{2}{M+1}

Hint: ##M+3 = (M+1) + 2##.
 
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