What is the Length of a Curve with Integrals?

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Homework Help Overview

The problem involves finding the length of a curve defined by the function f(x) = (1/12)(x - 48)√x for x ≥ 0, with a vertical line at x = 48. The original poster expresses concern about the behavior of the first derivative at x = 0, particularly regarding division by zero.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to apply the length of curve formula involving an integral but questions the validity of the derivative at x = 0. Other participants inquire about the final integral and the function's appearance post-integration.

Discussion Status

The discussion is ongoing, with participants exploring the implications of potential division by zero and suggesting the use of improper integral methods if necessary. There is no explicit consensus on the approach to take yet.

Contextual Notes

Participants are considering the implications of the function's behavior at x = 0 and the need for limits in the context of improper integrals. The original poster's concern about the first derivative's denominator introduces a critical point for discussion.

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Homework Statement



How can we found the length of the curve:
f(x) = \frac {1}{12}(x - 48)\sqrt x

where x\ge0 and the vertical line x=48.



Homework Equations





The Attempt at a Solution


I tried to use the formula L=\int^{48}_{0}\sqrt {1 + \ [f'(x)]^2} dx
But I think that there is a problem where x=0 because the first derivative is:
f'(x) = \frac {(x - 16) \sqrt {x}}{8x} and because x is in the denominator cannot take the value 0.

How can solve this issue??
Any ideas??
Thanks anyone in advance.
 
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What is the final integral? Do you know what the function looks like after the integral has been performed?
 
djeitnstine said:
What is the final integral? Do you know what the function looks like after the integral has been performed?

No I don't
 
You should try performing the integral before you ask whether or not there is division by zero. Perhaps there may be division by zero, in that case you will have to use the improper integral method (limit) to find out whether it converges or diverges at that point.
 

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