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C3 Functions

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    http://www.madasmaths.com/archive/iy...apers/c3_f.pdf

    Need help in part 8(c), how do we get the range over here as 0<f(x)<4? I tend to get confused when finding the range and domain of such situations. Could anyone tell me how to do so? TIA.
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    (Original post by sabahshahed294)
    http://www.madasmaths.com/archive/iy...apers/c3_f.pdf

    Need help in part 8(c), how do we get the range over here as 0<f(x)<4? I tend to get confused when finding the range and domain of such situations. Could anyone tell me how to do so? TIA.
    Draw a graph?
    For x > 1, the denominator is increasing as x increases, so f(x) is decreasing.
    As x tends to infinity, f(x) gets smaller and closer to zero.
    Then evaluate f(1).
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    (Original post by EricPiphany)
    Draw a graph?
    For x > 1, the denominator is increasing as x increases, so f(x) is decreasing.
    As x tends to infinity, f(x) gets smaller and closer to zero.
    Then evaluate f(1).
    So, you simply substituted x=1? Or you came to a conclusion by drawing out a graph?
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    (Original post by sabahshahed294)
    So, you simply substituted x=1? Or you came to a conclusion by drawing out a graph?
    Yes, substitution. Look at the graph, you don't even need to draw it. x>1 shows that you can ignore the left branch of it and since it is beyond the asymptote, the range will not involve infinity. So you can plug in x=1 and it will be everything between (and excluding including) f(1) and 0.
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    (Original post by RDKGames)
    Yes, substitution. Look at the graph, you don't even need to draw it. x>1 shows that you can ignore the left branch of it and since it is beyond the asymptote, the range will not involve infinity. So you can plug in x=1 and it will be everything between (and excluding including) f(1) and 0.
    Alright! Thank you.

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