Finding A Relative Condition Number

  • Thread starter Thread starter ver_mathstats
  • Start date Start date
  • Tags Tags
    Condition Relative
Click For Summary
SUMMARY

The discussion centers on calculating the relative condition number for the function f(x) = sqrt(x+1) - sqrt(x). The proposed formula for the relative condition number is k = (x/2)((1/sqrt(x+1)) - (1/sqrt(x))(1/(sqrt(x+1) - sqrt(x)))). Participants clarify that the limit should be evaluated as δx approaches 0, not as x approaches 0. The term "relative condition number" is defined in the context of numerical analysis, specifically in the Wikipedia article referenced.

PREREQUISITES
  • Understanding of numerical analysis concepts, particularly condition numbers.
  • Familiarity with limits in calculus.
  • Knowledge of square root functions and their properties.
  • Ability to parse and manipulate mathematical expressions.
NEXT STEPS
  • Study the definition and applications of condition numbers in numerical analysis.
  • Learn how to evaluate limits, specifically in the context of δx approaching 0.
  • Explore the implications of relative condition numbers in function stability.
  • Review mathematical expressions involving square roots and their derivatives.
USEFUL FOR

Students in mathematics, particularly those studying numerical analysis, as well as educators and professionals seeking to deepen their understanding of condition numbers and their applications in function analysis.

ver_mathstats
Messages
258
Reaction score
21
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.
 
Physics news on Phys.org
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.
 
  • Like
Likes   Reactions: anuttarasammyak

Similar threads

  • · Replies 3 ·
Replies
3
Views
1K
  • · Replies 30 ·
2
Replies
30
Views
3K
  • · Replies 2 ·
Replies
2
Views
2K
Replies
1
Views
1K
  • · Replies 5 ·
Replies
5
Views
2K
Replies
2
Views
2K
Replies
12
Views
2K
  • · Replies 12 ·
Replies
12
Views
3K
  • · Replies 14 ·
Replies
14
Views
2K
Replies
2
Views
2K