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Curve fitting an asymptote

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  • 10-05-2012 7:59pm
    #1
    Brussels Sprout
    Registered Users Posts: 6,609 ✭✭✭


    I'm trying to come up with an equation that represents some data points. The curve that they make looks like an asymptote. I've tried using the various trendline methods in excel and also the curve fitting methods on Wolfram Alpha but none of them are satisfactory, especially if I try and extrapolate.

    Do you know of any good methods that you would recommend in this scenario?

    These are the data points:


    X Y
    202 2
    201 2
    126 3
    101 4
    87 5
    78 6
    72 7
    67 8
    63.5 9
    60.5 10
    58 11
    56 12
    54.5 13
    50.5 16
    49.5 17
    47.5 19
    46 21
    44 24
    42 28
    40 33
    38 39
    37 44
    36 48
    35 54
    34 61
    33 69
    32 79
    31 91
    30 104.5
    29 124
    28 147
    27 177
    26 216
    25 268
    24 338
    23 436
    22 574
    21 777


Comments

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    #2
    ZRelation
    Registered Users Posts: 108 ✭✭ZRelation


    Have you tried a power law fit of the form y=A(x-B)^C in excel? Seems to give a reasonable fit..


  • Options
    #3
    ArmCandyBaby
    Closed Accounts Posts: 201 ✭✭ArmCandyBaby


    I looked at it wrong and found the inverse of the function you need just by messing around in excel. I tried to inverse it in alpha but it wouldn't work, it might be a start though if you still need it. I presume the 0.315990001137889 is the sqrt(10)/10 or something.

    x = 12.1763390842799 + 121.867195110183/(y - 1.07133792072276) + 72.29663973683/(y^0.315990001137889)


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