n.m

利用牛顿、拉格朗日、三次样条及线性插值方法拟合数据

function N =N(x)  %Newton
syms m
r=1/(1+m^2);
n=10;
y=1;
M=zeros(10);
X=-5:5;
N=subs(r,'m',X(1));
for i=0:n
    M(i+1,1)=subs(r,'m',X(i+1));
end
for i=2:n+1
    for j=i:n+1
        M(j,i)=(M(j,i-1)-M(j-1,i-1))/(X(j)-X(j-(i-1)));
    end
end
for i=2:n+1  
    y=y*(x-X(i-1));
    N=N+y*M(i,i);
end