untitled4.m

这是用牛顿法做的

x=[1 2 3 4];
y=[0.8 1.5 1.8 2.0];
x1=sum(x.^2);
x2=sum(x.^3);
x3=sum(x.^4);
x4=sum(x.*y);
x5=sum(x.^2.*y)
xi=[x1 x2;x2 x3]
yi=[x4;x5]
a=xi\yi
xx=1:0.001:4;
yy=0.94967741935484*(xx)+(-0.11290322580645).*xx.^2;
yy1=0.98720931.*xx+0.717054;
plot(xx,yy,'r',x,y,'o',xx,yy1,'k')