How to do curve fitting to a custom model with two independent variables?

I have data in which response is dependent upon two variables. Three data series are given:[x1, y1], [x2, y2], [x3, y3]. On excel (file attached) I have made XY scatter plot which gives three response curves. I want to fit these 3 curves to a custom model in the form: lnY = k*lnX + (a/T) + b This model is used to describe such data in our field. I just don't know how I will fit all three curves to this model? Please help!

Answer 1

[Matt J]

The independent variables are X and T? If you insist on using the Curve Fitting Toolbox, the thing to do would be to regard this as a surface in X and T and use sfit().

It is noteworthy, though, that your model is linear lnX and 1/T. So, you could really probably do a simple linear fit with mldivide(). In other words, just solve the linear equations for k, a, and b using normal linear algebraic operations.

[wahab maqbool]

@Matt J, yes X and T are independent variables. But can you please show how to fit this data to the model I provided? I mean, I have to fit it on that model. please help!

[Matt J]

What happened when you tried sfit()?