Trouble with the following limit

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Discussion Overview

The discussion revolves around evaluating the limit \(\lim_{x \rightarrow 0} \frac{1 - \sqrt{1 - 4x^2}}{x^2}\). Participants are comparing their results with a solution provided in a textbook (Apostol Volume I) and seeking clarification on the discrepancy.

Discussion Character

  • Mathematical reasoning, Debate/contested

Main Points Raised

  • One participant reports obtaining a limit of 2, while the textbook states the answer is 1/2.
  • Another participant suggests multiplying by \(\frac{1 + \sqrt{1-4x^2}}{1 + \sqrt{1-4x^2}}\) as a method to simplify the expression.
  • A third participant claims that l'Hôpital's rule supports their position and suggests that the discrepancy may be due to a typo in the textbook.

Areas of Agreement / Disagreement

There is disagreement regarding the correct value of the limit, with some participants supporting the original poster's result of 2 and others suggesting the textbook's answer of 1/2. The discussion remains unresolved.

Contextual Notes

Participants have not reached a consensus on the correct approach or result, and there may be assumptions regarding the application of l'Hôpital's rule that are not fully explored.

devious_
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I'm having trouble with the following limit:

[tex]\lim_{x \rightarrow 0} \frac{1 - \sqrt{1 - 4x^2}}{x^2}[/tex]

At the back of the book (Apostol Volume I), it says the answer is 1/2, but I get 2. Can anyone clarify?

Thanks.
 
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multiply by 1 :
[tex]\frac{1 + \sqrt{1-4x^2}}{1 + \sqrt{1-4x^2}}[/tex]

Seems to me you are correct
 
Yes,even l'Hôpital approves you guys.A typo in the book,nothing sensational.

Daniel.
 
Good to know. Thanks.
 

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