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Thread: Find f(-x)?

  1. #1
    la vache fantôme phantomcow2's Avatar
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    Find f(-x)?


    I am being prompted to find f(-x) of the following function:


    So plug in -x for x.

    (4*-x) + 1/(4*-x)

    -4x + 1/(-4x)

    Find a common denominator, which in this case is -4x. So, I multiplied the left term by (-4x)/(-4x)

    This gives me 16x^2 + 1/(-4x)

    Is that correct? I only have one attempt remaining in my web applet.
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  2. #2
    L T X B O M P F A N S R apricissimus's Avatar
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    The correct answer is (16x^2 + 1)/(-4x). You omitted the parentheses in the numerator, though I'm sure it was just an oversight.

  3. #3
    la vache fantôme phantomcow2's Avatar
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    Okay, well I did get that right. Now how about this:


    Find the domain.
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  4. #4
    la vache fantôme phantomcow2's Avatar
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    I'm stumped. At first I thought the domain would be [3,INF]. The reason being that 3 is the minimum number which can be inputted into this function and still get a real number. THe reason being the sqrt(x-3)
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  5. #5
    L T X B O M P F A N S R apricissimus's Avatar
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    That is the correct answer. Does your applet thingy (or whatever it is) say it's wrong?

    (BTW, my creds: BA in math; am currently an editor of math textbooks)

  6. #6
    L T X B O M P F A N S R apricissimus's Avatar
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    If you're typing in [3,INF], try typing [3,INF), since technically, an interval that does off to infinity is open on that end, not closed.

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