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Math Help - Non-Linear Least Square

  1. #1
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    Non-Linear Least Square

    Hi guys,

    I've been presented with a maths puzzle/equation to solve, but after some searching and an attempt at a self taught crash course I've still not been able to find a solution to this problem. So could anyone solve this please.

    I need to find the approx values of a-f in this equation.

    y = ax^5 - bx^4 + cx^3 - dx^2 + ex - f

    Where x and y are....

    x y
    -15 -5,439,067
    -10 -726,897
    -5 -24,127
    5 21,213
    10 685,283
    15 5,232953

    If anyone could solve this that would be great thanyou.

    Barry
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  2. #2
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    Re: Non-Linear Least Square

    You can solve this system of linear equations using WolframAlpha
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  3. #3
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    Re: Non-Linear Least Square

    Hi thanks for the link, but unless I'm missing something (and I literally have no idea at all) but I don't think that could work out non linear regression equations (not that I know exactly what that means but I think I get the gist). There's no-where to put parameters in. Or am I wrong?
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  4. #4
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    Re: Non-Linear Least Square

    Quote Originally Posted by Baz300 View Post
    Hi thanks for the link, but unless I'm missing something (and I literally have no idea at all) but I don't think that could work out non linear regression equations (not that I know exactly what that means but I think I get the gist). There's no-where to put parameters in. Or am I wrong?
    If you plug in values of x and y into starting equation you should obtain six equations with six unknowns (a,b,c,d,e,f)
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  5. #5
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    Re: Non-Linear Least Square

    Do you mean input the equation 6 times each with the different set of x and y values. I tried with one set and obviously it spouted out the equation back at me in a few different ways but no values for a to f.

    Thanks Barry
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  6. #6
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    Re: Non-Linear Least Square

    Quote Originally Posted by Baz300 View Post
    Do you mean input the equation 6 times each with the different set of x and y values. I tried with one set and obviously it spouted out the equation back at me in a few different ways but no values for a to f.

    Thanks Barry
    (a,b,c,d,e,f)=(7,2,6,8,9,7)
    Thanks from mash
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  7. #7
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    Re: Non-Linear Least Square

    I don't know how you did that but that's great, thanks so much for your time and patience.

    Regards, Barry
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