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Math Help - Question about Composition Functions

  1. #1
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    Question about Composition Functions

    Ok i know how to solve compositions when Im provided with x

    Here I am dealing with f of g of h

    f(x) = 2x-2
    g(x) = x^2
    h(x) = 9-x

    so its f(g(h(x)

    But how do i start without an x value?
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  2. #2
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    Re: Question about Composition Functions

    Quote Originally Posted by GaDoomZ View Post
    Here I am dealing with f of g of h
    f(x) = 2x-2
    g(x) = x^2
    h(x) = 9-x
    so its f(g(h(x))
    f \circ g \circ h(x) = f\left( {g\left( {h(x)} \right)} \right) = 2(9 - x)^2  - 2
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  3. #3
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    Re: Question about Composition Functions

    Oh I see haha, guess that was a stupid mistake on my part. Guess I just had to leave X as X...
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  4. #4
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    Re: Question about Composition Functions

    Ok how about
    f(x) = √x
    g(x) = 7√1-x

    I tried √7-x, √x, √7x they were all wrong
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  5. #5
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    Re: Question about Composition Functions

    Quote Originally Posted by GaDoomZ View Post
    Ok how about
    f(x) = √x
    g(x) = 7√1-x

    I tried √7-x, √x, √7x they were all wrong
    I don't know what you meant by "tried". Plato told you how to find the compositions.
     f\circ g(x)= f(g(x))= f(7\sqrt{1-x}}= \sqt{7\sqrt{1-x}}
    which could also be written
    \sqrt{7}\sqrt[4]{1- x}

    g\circ f(x)= g(f(x))= g(\sqrt{x})= 7\sqrt{1- \sqrt{x}}
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  6. #6
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    Re: Question about Composition Functions

    When I submitted both of those, it was marked as wrong...
    even after simplfying it down to

    √7-x and 7-√x
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  7. #7
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    Re: Question about Composition Functions

    Quote Originally Posted by GaDoomZ View Post
    When I submitted both of those, it was marked as wrong...
    even after simplfying it down to

    √7-x and 7-√x
    \sqrt{7\sqrt{1-x}}
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  8. #8
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    Re: Question about Composition Functions

    Nope, still didn't work... I am out of submissions now
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  9. #9
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    Re: Question about Composition Functions

    Quote Originally Posted by GaDoomZ View Post
    Nope, still didn't work... I am out of submissions now
    I am now stuck on G o G of the same problem

    I get 7√1-7√1-x which should just be 7√1-x no?
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  10. #10
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    Re: Question about Composition Functions

    Quote Originally Posted by GaDoomZ View Post
    I am now stuck on G o G of the same problem

    I get 7√1-7√1-x which should just be 7√1-x no?
    I think that there must be a flaw in what program you are using.

    If this is indeed correct g(x)=7\sqrt{1-x}

    then g\circ g(x)=7\sqrt{1-7\sqrt{1-x}~}.

    If the program does not take that, then either you are typing the symbols incorrectly or there is a flaw in the program.
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  11. #11
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    Re: Question about Composition Functions

    Quote Originally Posted by Plato View Post
    I think that there must be a flaw in what program you are using.

    If this is indeed correct g(x)=7\sqrt{1-x}

    then g\circ g(x)=7\sqrt{1-7\sqrt{1-x}~}.

    If the program does not take that, then either you are typing the symbols incorrectly or there is a flaw in the program.
    Nope it is showing up as incorrect still
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  12. #12
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    Re: Question about Composition Functions

    Quote Originally Posted by GaDoomZ View Post
    Nope it is showing up as incorrect still
    Then that is a totally incompetent program or you do not know how to use it. I suspect that you are not using enough grouping symbols.
    Look at my LaTeX code:
    7\sqrt{1-7\sqrt{1-x}} this gives 7\sqrt{1-7\sqrt{1-x}}.
    Note how carefully the various parts are grouped together using grouping symbols.

    Does that program allow LaTeX coding?
    If so the you can copy and paste from here.

    In any case, you need to contact the program administrator to discuss these concerns.
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  13. #13
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    Re: Question about Composition Functions

    You are correct plato, I was not inputting the second 7 properly. Thank you again
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