title: exponential curve fitting with 3 coefficients
body: <p>I have some data (two same size vectors X and Y) and would like to fit an exponential function as <code>f(x)=a+(b-a)*exp(-c*x)</code> to this data by MATLAB. My goal is actually to find  coefficients a, b and c.</p>
  
  <p>I found <code>fit(X,Y,'exp2')</code> and <code>fit(X,Y,'exp1','StartPoint',[x0,y0])</code> in MATLAB manual which are a little different than what I am looking for.</p>