I have a non-linear equation with 3 variables I wish to be constants and only 1 variable to be fitted to x,y data.
Using fittype, I have entered the equation and tried to specify b, c & d as constants. However, the options ‘problem’ only seems to allow single variables to be specified as constants
ft = fittype(@(a, b, c, d,x) a*c*x./(1+c*x) + b*d*x./(1+d*x),’problem’,’b,c,d’);
Error using fittype>iAssertValidVariableNames
The name ‘[b,c,d]’ is not a valid MATLAB variable name.

In the next part I use "fit" to fit the data, and specify the value of the 3 constants and starting point of the fit:
f = fit(p(1:index),q(1:index),ft,’problem’,[Qm2 b1 b2],’StartPoint’,Qm1);
Is there another way to specify constants in the fittype?I have a non-linear equation with 3 variables I wish to be constants and only 1 variable to be fitted to x,y data.
Using fittype, I have entered the equation and tried to specify b, c & d as constants. However, the options ‘problem’ only seems to allow single variables to be specified as constants
ft = fittype(@(a, b, c, d,x) a*c*x./(1+c*x) + b*d*x./(1+d*x),’problem’,’b,c,d’);
Error using fittype>iAssertValidVariableNames
The name ‘[b,c,d]’ is not a valid MATLAB variable name.

In the next part I use "fit" to fit the data, and specify the value of the 3 constants and starting point of the fit:
f = fit(p(1:index),q(1:index),ft,’problem’,[Qm2 b1 b2],’StartPoint’,Qm1);
Is there another way to specify constants in the fittype? I have a non-linear equation with 3 variables I wish to be constants and only 1 variable to be fitted to x,y data.
Using fittype, I have entered the equation and tried to specify b, c & d as constants. However, the options ‘problem’ only seems to allow single variables to be specified as constants
ft = fittype(@(a, b, c, d,x) a*c*x./(1+c*x) + b*d*x./(1+d*x),’problem’,’b,c,d’);
Error using fittype>iAssertValidVariableNames
The name ‘[b,c,d]’ is not a valid MATLAB variable name.

In the next part I use "fit" to fit the data, and specify the value of the 3 constants and starting point of the fit:
f = fit(p(1:index),q(1:index),ft,’problem’,[Qm2 b1 b2],’StartPoint’,Qm1);
Is there another way to specify constants in the fittype? curve fitting MATLAB Answers — New Questions

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