編寫程序如下:
x = (0: 5);
y = rand(1,6);
p = polyfit(x,y,3)%p是多項式系數
f = polyval(p,x);
plot(x,y,'o',x,f,'-')
壹、x=[1.75,2.25,2.5,2.875,2.686,2.563];y=[0.26,0.32,0.44,0.57,0.50,0.46];plot(x,y,'g.','markersize',25);%%%有這個是先描點,看出大致是什麽圖,這裏看到像二次曲線的。hold?on?;p3=polyfit(x,y,2)。
二、同理x=[0.26,0.32,0.44,0.57,0.50,0.46];y=[1.75,2.25,2.5,2.875,2.686,2.563];plot(x,y,'g.','markersize',25);hold?on?;p3=polyfit(x,y,1);x2=0:0.5:2;y2=3.3237*x2+1.0247;plot(x2,y2,'b')。
三、代碼:clear all;clc;close all;x=[1.75,2.25,2.5,2.875,2.686,2.563];y=[0.26,0.32,0.44,0.57,0.50,0.46];plot(x,y,'r*')[p,s]=polyfit(x,y,5) ?%參數改為1就是線性擬合y1=polyval(p,x)hold on;plot(x,y1,'b.')五次多項式擬合生成的函數值與原數據基本重合。