Validating the Limit of the Square Root Function

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The discussion centers on proving the limit lim x -> x_0 sqrt(x) = sqrt(x_0) using the definition of limits. The user expresses confusion about starting the proof and attempts to manipulate the expression |sqrt(x) - sqrt(x_0)| to show it is less than epsilon when |x - x_0| is less than delta. They derive a relationship involving |sqrt(x) + sqrt(x_0)| and consider bounding it by assuming delta is small. The user acknowledges that the problem is becoming clearer with guidance and intends to share their progress once they understand it better. The conversation highlights the importance of understanding the limit definition in calculus.
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.
 
Question: A clock's minute hand has length 4 and its hour hand has length 3. What is the distance between the tips at the moment when it is increasing most rapidly?(Putnam Exam Question) Answer: Making assumption that both the hands moves at constant angular velocities, the answer is ## \sqrt{7} .## But don't you think this assumption is somewhat doubtful and wrong?

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