Two exponential curve fitting

Hi all,

I want to fit my data to a particular type of equation and get the values of the constant. The function is of the following form

F= A*exp(-B*x)-C*exp(-D*x)

I wish to find the values of A, B, C and D. How do I go about doing this in Matlab.

Thanks for the help.

Nancy

Answer 1

[Andrew Newell]

You'll find this problem described on this support page.

Answer 2

[Ada Verónica Elizabeth]

Using the data x,F where x is the ordered set of independent values and F is the data corresponding to:

Model = fit(x,F,"exp2");

values = coeffvalues(Model);

values %contains coefficients a,b,c,d for F=a*exp(b*x)+c*exp(d*x)

a= values(1)

b= values(2)

d= values(3)

d= values(4)