On Thu, 17 Mar 2005 00:25:44 +0100, "Darius Blaszijk"
wrote:

Hello,

I have the following data;

y x1 x2
12 1 10
23 2 20
34 3 30
45 4 40
56 5 50


And I would like to fit the following formula to this dataset; "x1^2 + x2 *
x1 = y"

Can anybody give me a pointer on how to do this, preferebly without having
to linearize the dataset first? The "algorithm" proposed should however be
able to fit any formula / model to the dataset, eg be general about this.

Kind regards, Darius Blaszijk


You seem to be missing something. You can't fit the formula as you wrote it.

What coefficients are you trying to determine? Do you really mean you are
trying to find "a" and "b" that best fit the equation y = a*x1^2 b*x1*x2,
or y= a*x1*(x1 + b*x2) or y= x1*(a*x1+b*x2), or something else?

--
Jay.
(remove dashes for legal email address)