Finding A Relative Condition Number

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Homework Statement
Find the relative condition number for f(x)=sqrt(x+1)-sqrt(x).
Relevant Equations
f(x)=sqrt(x+1)-sqrt(x).
Hm I'm new to these concepts, and I want to make sure I am on the right track, would the relative condition number be:

k=(x/2)((1/sqrt(x+1))-(1/sqrt(x))(1/(sqrt(x+1)-sqrt(x))). Or would I have to solve the limit as x approaches 0?

Thank you.
 
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I know condition number in numerical analysis but what is the concept or definition of "relative condition number" you say?
 
ver_mathstats said:
Homework Statement:: Find the relative condition number for f(x)=sqrt(x+1)-sqrt(x).
Relevant Equations:: f(x)=sqrt(x+1)-sqrt(x).

Hm I'm new to these concepts, and I want to make sure I am on the right track, would the relative condition number be:

k=(x/2)((1/sqrt(x+1))-(1/sqrt(x))(1/(sqrt(x+1)-sqrt(x))). Or would I have to solve the limit as x approaches 0?

Thank you.
  1. I'm reasonably sure your equation above is written correctly, but it's really hard to parse.
  2. I'm not familiar with the term "relative condition number," but this wikipedia article (https://en.wikipedia.org/wiki/Condition_number) provides a definition. The section titled "Several variables" defines the term "relative condition number."
  3. From the above definition, the limit is on ##\delta x##, not x.
 
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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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