Can some please help me solve the error in the file

Questions
,
1

HI,
I am trying to fit model to data, but it is showing an error. Can someone please help me with this. I have attached the mathematica file for the reference.

Thanks,
Jaydeep

2

The error message tells you exactly what the problem is. It expects a symbol, but you gave it a real.

3

HI,
Thanks for the reply,
But then usually I do the fitting procedure the same way, and it has worked earlier. I am attaching a file where it had worked fine. I am not able to find why the same code is not working in the above file.
I will appreciate, if you can please help me find out my mistake.

Thanks

4

There are a couple of problems I see (note that I’m not looking at your input carefully):

  1. Model3 is a function of 2 variables. When calling our fitting function, you give it 3 variables. One of these is wrong.

    Model3[ka_?NumericQ, te_]

  2. You are missing a set of braces in the fitting function. It should look something like this:

    fit = NonlinearModelFit[data, {Model3[ka, te]}, {{ka, 1.67}}, {te}]

5

In the line

fit = NonlinearModelFit[   data, {Model3[ka, Cc, te]}, {ka, 1.67}, {Cc, te}]

{ka, 1.67} is supposed to be a list of parameters to vary. 1.67 is a constant.