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Math Help - composition

  1. #1
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    composition

    find f * g if f(x) = x^2-7 and g(x) = 2x+4
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  2. #2
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    do i combine the two equations?
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  3. #3
    Forum Admin topsquark's Avatar
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    Quote Originally Posted by aikenfan View Post
    find f * g if f(x) = x^2-7 and g(x) = 2x+4
    It depends.
    (f * g)(x) = (x^2 - 7)(2x + 4)
    if this is multiplication of functions.

    If it is composition of functions:
    (f \circ g)(x) = f(g(x)) = f(2x + 4) = (2x + 4)^2 - 7

    -Dan
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  4. #4
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    It is this:
    (f \circ g)(x) = f(g(x)) = f(2x + 4) = (2x + 4)^2 - 7
    but i am a bit confused
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  5. #5
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    Krizalid's Avatar
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    I think aikenfan asked for (f\circ{g})

    (f\circ{g})=f(g(x))=(g(x))^2-7=(2x+4)^2-7

    Which is the same result of Dan
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