Validating the Limit of the Square Root Function

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SUMMARY

The discussion focuses on proving the limit of the square root function, specifically lim x -> x_0 sqrt(x) = sqrt(x_0). The user attempts to apply the definition of a limit, starting with the inequality |sqrt(x) - sqrt(x_0)| < epsilon and exploring the relationship between delta and epsilon. The conversation highlights the manipulation of the expression |sqrt(x) - sqrt(x_0)| using the identity |sqrt(x) - sqrt(x_0)| = |x - x_0| / |sqrt(x) + sqrt(x_0)|, emphasizing the importance of bounding |sqrt(x) + sqrt(x_0)| for small delta values.

PREREQUISITES
  • Understanding of limit definitions in calculus
  • Familiarity with the properties of square root functions
  • Knowledge of epsilon-delta proofs
  • Basic algebraic manipulation skills
NEXT STEPS
  • Study epsilon-delta definitions of limits in calculus
  • Explore the properties of square root functions and their continuity
  • Practice proving limits using algebraic manipulation techniques
  • Review examples of limit proofs involving square roots
USEFUL FOR

Students in calculus courses, mathematics educators, and anyone interested in mastering limit proofs and the properties of square root functions.

StarTiger
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Could someone help me with this? I feel it should likely be easy, but I'm baffled anyway:

Homework Statement



Prove the validity of the limit lim x -> x_0 sqrt(x) = sqrt(x_0)

Homework Equations



use definition of limit

The Attempt at a Solution



Generally confused. I start with |sqrtx - sqrtx0| < epsilon
 
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You want to show that for any delta > 0, there is an epsilon so that |sqrt(x) - sqrt(x_0)| < eps when |x - x_0| < delta.

|sqrt(x) - sqrt(x_0)| = |sqrt(x) - sqrt(x_0)| *|sqrt(x) + sqrt(x_0)| /|sqrt(x) + sqrt(x_0)| = |x - x_0|/ *|sqrt(x) + sqrt(x_0)|

Without loss of generality, you can assume that delta is reasonably small, say less than 1. That puts x within 1 unit of x_0.

Can you work with |sqrt(x) + sqrt(x_0)| to find max and min values for it?
 
Okay...this is starting to make more sense now. Thanks for the tips. When I get it I'll try to upload what I have.
 

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