clear
x1=[5.20 8.17 9.79 11 12.33 19.07];
y1=[9.67 61.84 79.14 84.51 89.13 100];
y1i=9.67:0.001:100;
x1i=pchip(y1,x1,y1i);
p=polyfit(y1i,x1i,3)%用polyfit进行3次多项式拟合慧凳滑
%结果为p = 0.0000 -0.0058 0.2698 2.3263
f = polyval(p,y1i);
plot(y1i,x1i,'o',y1i,f,'-')
plot(y1i,x1i,'o',y1i,f,'-')%查看拟合结前腊粗团果