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Math Help - What is an undefined value? (see question inside)

  1. #1
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    What is an undefined value? (see question inside)

    Started a new online course to try and get better at math, but the course has a few dead links and I'm missing some information. I have this question:

    "For what values are the following undefined"

    x^2 - 2x + 3
    ___________
    x^2+2x+1

    first I expand

    x^2- 2x + 3
    __________
    (x+1)(x+1) [or x+1^2]

    Then I don't know what to do.

    I've looked at the easier examples they give me and when they give an answer for an "undefined value" it is the x-intercepts/zeros of the function. Can someone explain to me what exactly they mean by "undefined values"
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  2. #2
    MHF Contributor ebaines's Avatar
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    Re: What is an undefined value? (see question inside)

    The original equation is undefined if the denominator = 0. So in this case it's undefined if x^2+2x+1 = 0, which as you demonstrated means it's undefined if (x+1)^2 = 0. For what value(s) of x does (x+1)^2 = 0?
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    Re: What is an undefined value? (see question inside)

    Okay that makes more sense, im not sure if I'm understanding that last part right but does x=-1. I'm not sure how to phrase the answer
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    MHF Contributor ebaines's Avatar
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    Re: What is an undefined value? (see question inside)

    Right - you say the function is undefined for x = -1. To test this, try putting -1 in place of x in the denominator of the original equation - if the denominator turns out to be 0, then the function is undefined at that point.
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