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Math Help - help with composite functions

  1. #1
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    help with composite functions

    Given that f(x)= x^2 and g(x)=4x-1 find the value of the following

    a) gf(-3)
    b) fgf(-1)
    c) gfgf(2)

    I think i can do a but i dont know the way of doing b and c

    is a correct?

    gf(-3)= g(f(-3))

    f(-3)= -3^2 = 9

    g(9)= 4(9)-1 = 35
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  2. #2
    Senior Member apcalculus's Avatar
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    correct!

    follow the same logic, except you're plugging in three times, starting with the inner function and evaluating its output in the next function out.
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  3. #3
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    Im solving such questions for the first time..
    so for b

    fgf(-1)= fg(f(-1))

    f(-1)= x^2= -1^2=1

    but i dont know how to continue..?
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  4. #4
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    is it like this..

    fg(1)= f(g(1))

    g(1)= 4(1)-1

    =3

    ?
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