Dear Community:
I am a very new user of MathCad, and I need help understanding the syntax of the linfit function. (At least I think it's a syntax issue).
I built a small worksheet to look at various curve fitting functions (it grew out of a need from a work related worksheet; I have hand entered some of the data and changed to units to make the example sheet self-contained). I successfully parroted the linfit example for a quadratic fit (a*x^2+b*x+c), but I could not extend it successfully for a cubic fit (a*x^3+b*x^2+cx+d). I could successfully build a cubic fit using polyc.
I enclose the worksheet:
Page 1: Data
Page 2: Cubic Spline
Page 3: Straight Line
Page 4: Quadratic linfit (and polyc)
Page 6: Cubic linfit (and polyc) <---- This is where it goes wrong
Any insights would be appreciated.
Regards,
Bob