Quadratic fitting of data

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@GvanBoven wrote:

Hello everyone

 

Attached to this post is a zip file with prime 3 sheet and an excel with the data. I need to fit this data using the following equation:

 

y = ax^2+bx+c

 

So why are you using pwrfit?? pwrfit (lookup the help!= tries to fit y=a*x^b+c and that has nothig to do with the quadratic fit you are looking for.

There are several way that this can be done in Prime

1) Use "polyfit". If you need to see the coefficients a,b,c, then use polyfitc

2) Use "linfit" with a vector consisting of 1,x and x^2 as function argument

3) Use "genfit". You can fit your data to any function you define with any number of parameters.

 The function you want is not pwrfit, you want polyfit.