%%%%%%% matlab程序   多项式拟合

clc
x = [1   2    3   4     5     6     ];  %data
y = [5.5 43.1 128 290.7 498.4 978.67];  %data
p = polyfit(x,y,4)                      %p为拟合函数的系数

x2 = 1:.1:6;          
y2 = polyval(p,x2);          
plot(x,y,'o',x2,y2);
grid on
disp(char(['y=',poly2str(p,'t')]))
legend('y','y2')
%disp(char(['y=',poly2str(p,'t')],['a=',num2str(p(1)),' b=',num2str(p(2)),' c=',num2str(p(3))]));

另一个例子：

%%%%% matlab函数   

clc;
x = linspace(0,1,5)
y = 1./(1+x)
p = polyfit(x,y,4)
x1 = linspace(0,2);
y1 = 1./(1+x1);
f1 = polyval(p,x1);
figure
plot(x,y,'o')
hold on
plot(x1,y1)
plot(x1,f1,'r--')
legend('y','y1','f1')

参考：https://ww2.mathworks.cn/help/matlab/ref/polyfit.html  拟合

     https://www.cnblogs.com/farewell-farewell/p/7227516.html  拟合