% xPolyfitLinear.m
%
% % 函數polyfit()的應用示例---用于單變量線性擬合
% 
%   Author: HUANG Huajiang
%   Copyright 2003 UNILAB Research Center, 
%   East China University of Science and Technology, Shanghai, PRC
%   $Revision: 1.0 $  $Date: 2003/02/25 $

clear all
clc

xi = [1.00	1.25	1.50	1.75	2.00];
yi = [5.10	5.79	6.53	7.45	8.46];
Lnyi = log(yi);

p = polyfit(xi,Lnyi,1)   % “1”指定線性擬合，擬合：lny=bx+lna
b = p(1)
Lna = p(2);
a = exp(Lna)

x = linspace(xi(1),xi(end),100);
Lny = polyval(p,x)
plot(xi,Lnyi,'o',x,Lny,'-')
xlabel('x')
ylabel('lny')