Curve Fitting

Posted in: , on 31. Jan. 2008 - 17:40


I need to calculate the parameters of the following equation:

S = (a + ((b-a)/(1+((2*pi*x)^2*c^2))))

I have the measured data of S and need the parameters a,b and c to get a curve fit in the software for analysis.

If someone can help me in this regard or suggest any software that can perform this thing for me?


Re: Curve Fitting

Posted on 31. Jan. 2008 - 08:28

dear Mr ,

You have an equation with 3 unknown parameters (a, b and c).

Take 3 values of your measurements.

Then you have 3 equations with 3 unknown parameters and those should be solved.

Repeat this procedure several times for different values of S and average the results for a, b, and c.

Otherwise, plot your data in a spreadsheet and use the regression line feature.




Re: Curve Fitting

Posted on 4. Feb. 2008 - 11:59

Thanks Teus!!

But there is no easy way, because in anoyher equation, i have five unknowns!!!!!

Re: Curve Fitting

Posted on 4. Feb. 2008 - 06:25

dear Mr ,

If you have 5 unknowns. then you need 5 equations to solve the unknowns.

(If you can find a mathematical relationship)

keep on trying