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Is this function correct? (Not a homework Question)

  1. Feb 28, 2013 #1
    I was bored and decide to make a function (yes, i am a bit weird). So I came up with this:

    f(x)=2x+3
    g(f)= f+2
    w(g)=g2+3

    x=2

    f(2)=4+3
    f(2)=7
    g(7)=7+2
    g(7)=9
    w(9)=81+3
    w(9)=82

    Is those working outs correct or not? If it isn't could you tell me where i got it wrong?
     
  2. jcsd
  3. Feb 28, 2013 #2
    As long as you mean g(f(x)) and w(g(f(x))), then you have the right answer
     
  4. Feb 28, 2013 #3

    HallsofIvy

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    Yes, what you have is correct. More generally, with f(x)= 2x+ 3, g(x)= x+ 2, and [itex]w(x)= x^2+ 3[/itex], [itex]g(f(x)= (2x+ 3)+ 2= 2x+ 5[/itex] and [itex]w(g(f(x)))= (2x+ 5)^2+ 3= 4x^2+ 20x+ 28[/itex].

    Evaluating that at x= 2 gives 4(4)+ 20(2)+ 28= 16+ 40+ 28= 84.
     
  5. Feb 28, 2013 #4
    Thanks for your time on here!! :-)

    -QuantumPixel
     
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