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Homework Help: Graph and inverse

  1. Dec 15, 2004 #1
    I have a graph that looks like a C its a parabola and it has a vertex of -2,0 My question says to evaluate f(2) f(-2) f^-1(0) and f^-1(2) how do I do this? I sketched the inverse already now what? Please help me
     
  2. jcsd
  3. Dec 15, 2004 #2
    Find the values of [itex]y[/itex] when [itex]x[/itex] equals each of those values for each graph. For example, find the [itex]y[/itex] coordinate for the point on [itex]f(x)[/itex] where [itex]x=2[/itex] to evaluate [itex]f(2)[/itex]. It may be useful to find the equations of the functions first. Try using the data and the graph to find the equations.
     
  4. Dec 16, 2004 #3
    Another thing: in an inverse the x and y values are switched. This fact makes drawing even the most complcated graph's inverses a breeze. :approve:
     
  5. Dec 16, 2004 #4

    HallsofIvy

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    Darned if I know! You will need to know more about the function than just that its graph "looks like a C its a parabola and it has a vertex of -2,0". From that, you can only say that f-1(0)= -2 since the inverse function swaps x and y values.
    f(2) and f-1 depend upon other information about the graph.
     
  6. Dec 17, 2004 #5

    LOL thanks guys I got it, I found the coordinates of f(x) and then switched them to get the inverse. Then I evaluated I hope this is right. :smile:
     
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