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Composition of functions (in set)

  1. May 13, 2009 #1
    1. The problem statement, all variables and given/known data

    A = {0, 1, 2, 3} f and g are fucntions mapping A to A where
    f = {(0,1),(1,2),(2,0),(3,3)} and g = {(0,2),(1,3),(2,0),(3,1)}

    (f o g)(1)

    2. Relevant equations

    3. The attempt at a solution

    The answer is 3 but i can not get it..
    the (1) on the right side means find the y value whem x = 1
    I think my (f o g) thing is not correct but i dont know how to do this..
    book just gave me an example but that is totally different from this one.
  2. jcsd
  3. May 13, 2009 #2


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    You know that [itex](f \circ g)(x)=f(g(x))[/itex]?. Can you tell us what value g(1) has?
    Last edited: May 13, 2009
  4. May 13, 2009 #3
    g(1) would be 3 as g has point (1,3)
  5. May 13, 2009 #4
    Ohh i got it.
    g(1) is 3 and as f has point (3,3) the answer is 3
  6. May 13, 2009 #5


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    Yep that is correct. Now what is the value of f(3)?

    Edit: Seems you beat me to it! Yes that's all correct.
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