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Math Help - Graphing function

  1. #1
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    Question Graphing function

    I am to take f(x)=x^2-4, flip it vertically, then move it up 8 units.
    Here is the picture of the graph, I am supposed to match f(x) to g(x).


    The answer I keep getting is -(x^2-4)+8, but that is incorrect. Please help me understand why.
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  2. #2
    Senior Member MacstersUndead's Avatar
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    Why is it incorrect?

    If you meant "reflect it with respect to the x-axis" then
    y = x^2 - 4 is translated to -y = x^2 - 4

    so then you have y = -x^2 + 4

    moving it up 8 units is a vertical translation of 8, so y = -x^2 + 12. (which is what you have but not simplified)

    If it was meant to be read reflection about the y-axis, then x -> -x, so that y = x^2 - 4. add 8 makes it y = x^2 + 4
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  3. #3
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    Quote Originally Posted by md56 View Post
    I am to take f(x)=x^2-4, flip it vertically, then move it up 8 units.
    Here is the picture of the graph, I am supposed to match f(x) to g(x).


    The answer I keep getting is -(x^2-4)+8, but that is incorrect. Please help me understand why.
    f(x)=x^2-4 \ is \ a\  parabola\

    so\ on\ flip\ it\ vertically,\ and\ then\ move\ it\ up\ 8\ units\quad g(x)=-(x^2-4)+8
    Last edited by ramiee2010; October 17th 2009 at 11:04 AM. Reason: typo
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  4. #4
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    Oh I see my mistake. Though I do not entirely understand why it is a mistake. Why is the negative not distributed to the 4 if to flip a function vertically you must -f(x)
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