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Math Help - Evaluate Limits

  1. #1
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    Evaluate Limits

    Hello,

    Can someone please help me solve this problem?

    Evaluate

    Lim [x^2+2x+1 / x^4 - 1]
    x --> -1

    got it down to about this:

    2x+1 / (x-1)(x^2-1)

    what should I do next?
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  2. #2
    Super Member bigwave's Avatar
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    Quote Originally Posted by l flipboi l View Post
    Hello,

    Can someone please help me solve this problem?

    Evaluate

    Lim [x^2+2x+1 / x^4 - 1]
    x --> -1

    got it down to about this:

    2x+1 / (x-1)(x^2-1)

    what should I do next?
    \lim_{x \to -1}\frac{x^2+2x+1}{x^4-1}



    \lim_{x \to -1}\frac{(x+1)(x+1)}{(x+1)(x-1)(x^2+1)}<br />
\Rightarrow <br />
\lim_{x \to -1}\frac{(x+1)}{(x-1)(x^2+1)}<br />
\Rightarrow <br />
\frac{0}{-4} = 0

    you can also use L'Hospitals Rule
    Last edited by bigwave; January 19th 2010 at 07:31 PM. Reason: more steps
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  3. #3
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    I'm trying to avoid getting 0 in my denominator when I plug in X=-1. Does that mean that the solution "does not exist"?
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