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Math Help - Evaluating a limit

  1. #1
    Senior Member Stroodle's Avatar
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    Evaluating a limit

    Hi,

    I don't know where to start with this problem.
    I'm trying to evaluate the limit as x goes towards 7 of ((x+2)^(1/2)-3)/(x-7).
    The answer is 1/6 according to my text.
    Sorry, my latex skills are a bit rusty...

    THanks.
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  2. #2
    Junior Member
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    Re: Evaluating a limit

    L'Hopital's rule should work.
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  3. #3
    Senior Member Stroodle's Avatar
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    Re: Evaluating a limit

    Awesome, thanks. Looks like I'm learning that rule next lecture.
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  4. #4
    MHF Contributor chisigma's Avatar
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    Re: Evaluating a limit

    Quote Originally Posted by Stroodle View Post
    Hi,

    I don't know where to start with this problem.
    I'm trying to evaluate the limit as x goes towards 7 of ((x+2)^(1/2)-3)/(x-7).
    The answer is 1/6 according to my text.
    Sorry, my latex skills are a bit rusty...

    THanks.
    If You multiply numerator and denominator by \sqrt{x+2}+3 , You will 'discover' that a confortable simplification is possible...

    Kind regards

    \chi \sigma
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  5. #5
    Super Member TheChaz's Avatar
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    Re: Evaluating a limit

    Quote Originally Posted by Stroodle View Post
    Hi,

    I don't know where to start with this problem.
    I'm trying to evaluate

    \lim_{x \to 7} \frac{\sqrt{x + 2} - 3}{x - 7}

    The answer is 1/6 according to my text.
    Sorry, my latex skills are a bit rusty...

    THanks.
    Multiply by the conjugate on top and bottom... L'Hospital's rule isn't necessary


    (edit... right, what HE said!)
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