Data fitting Questing (A+Bx^c)


(Lonely917) #1

I am amazing about mathnet,and it helps me a lot.
Now I am wondering how to do fitting for this y = A+Bx^c. I have known the Power Fit and looked Linearizing non-linear models by transformation topics but I still have no solution.


(Peter Vanderwaart) #2

There a couple of approaches to this problem in previous questions. Look for How to find the parameters of Herschel-Bulkley model through Nonlinear Regression!, and for my post Exponential Fit. The solutions are obtain by a nested or two-step process.


(Lonely917) #3

txg
I used power fit to fit y = a*x^b,I see it deal this by transforming it to a linear fit model, but the result shows above. I was wondering whether it is fitting enough? Maybe non-linear fit(eg. Gauss-Newton Method) will get better result? the red line for the original data, the blue line for the fitting line