simulataneous Curve fitting follow up

as a follow up to this question http://mathworks.com/matlabcentral/answers/13459-simulataneous-curve-fitting

Is there a simple modification that I can make that would allow me to instead simultaneously graph curves with this equation:

y=a log(x+d)

y=b log(x+ 2*d)

y=c log(x+ 3*d)

[Fangjun Jiang]

You previous question said. Please be precise.

The equations that I want to do the fitting with are:

y= a log x + b

y= c log x + 2* b

y= d log x + 3 *b

[Syd]

i already got that question answered...this is a second question. thanks

Answer 1

[bym]

y(:,1)=a*log(x+d);
y(:,2)=b*log(x+2*d);
y(:,3)=c*log(x+3*d);
plot(x,y)

Answer 2

[Friedrich]

Hi,

I think this won't work since you can't seperate the unknowns as needed. I can't think on any easy way to do it. I can't think on a way to do it (without writing the fitting algorithm by your own) in MATLAB at all.