Limit of a function with a radical in numerator

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SUMMARY

The limit of the function \(\frac{\sqrt{x+4}-2}{x}\) as \(x\) approaches 0 can be evaluated using the technique of rationalizing the numerator. The discussion highlights that the function is continuous, allowing the limit to be computed directly at \(x=0\). By substituting \(x\) with values approaching 0 from both sides, the limit converges to 0.25, confirming the result through both numerical approximation and algebraic manipulation.

PREREQUISITES
  • Understanding of limits in calculus
  • Familiarity with rationalizing expressions
  • Knowledge of continuous functions
  • Basic algebraic manipulation skills
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  • Study the method of rationalizing numerators in limit problems
  • Explore the properties of continuous functions in calculus
  • Learn about L'Hôpital's Rule for indeterminate forms
  • Practice evaluating limits using numerical approximation techniques
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Students studying calculus, particularly those learning about limits and continuity, as well as educators seeking to enhance their teaching methods in these topics.

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Homework Statement



Evaluate the limit as x → 0 (zero), if it exists, for:
[(x+4)^(1/2) - 2]/x

The Attempt at a Solution



I was not too sure at an elegant solution because nothing like this existed in the coursework. The best I could think of was to evaluate the limit on each side of zero.

I tried: evaluate x → 0+ (I used 0.000001)., then I tried: evaluated x → 0- (I used -0.000001). Both of these values are very close to 0.25.

How can I solve this problem with a little more elegance? Many thanks to the repliers!
 
Last edited:
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That function, [tex]\dfrac{\sqrt{x+ 4}- 2}{2}[/tex], is made entirely of continuous functions so is continuous itself. The limit "as x goes to 0" is simply the value at x= 0.
 
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I don't know if the OP had a typo and fixed it or whether Halls miscopied it but given the expression is$$
\frac{\sqrt{x+ 4}- 2}{x}$$try rationalizing the numerator.
 

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