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11-29-2012
12:05 PM

11-29-2012
12:05 PM

How to curve fit a function of two variables

Hi,

I have a set of data for a function of two variables f(x1,x2). My function is exponential for x1 with two coefficients that depend on x2:

f(x1,x2)=a*(x1)^b, where a and b are functions of x2.

I found a and b for several values of x2, so I do have equations f(x1) for some fixed x2. I am now trying to find a general equation f(x1,x2).

Is there a way to do curve fitting with two variables-- Mathcad help shows only how to curve fit with one variable?

Every input is appreciated.

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3 REPLIES 3

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11-29-2012
03:58 PM

11-29-2012
03:58 PM

Re: How to curve fit a function of two variables

If you have Mathcad 15 or Prime, then you could try the multivariate fitting function **multidfit**. Otherwise, a solve block will probably handle your problem.

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11-29-2012
04:26 PM

11-29-2012
04:26 PM

Re: How to curve fit a function of two variables

See the attached worksheet

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11-29-2012
07:32 PM

11-29-2012
07:32 PM

Re: How to curve fit a function of two variables

Stuart and Richard,

Thanks for your replies. I'll try to digest your suggestions.

Lazar