function yy=newton(x0,y0,x)
%newton插值，求數據(x0,y0)所表達的函數在插值點x處的插值
n=length(x0);
m=length(x);
for k=1:m
    for i=1:n
        a=0;
        b=1;
        c=1;
        yy0=0;
        for j=1:i
            for l=1:i
               if l~=j
               b=b*(x0(j)-x0(l));
               end
            end
            a=a+y0(j)/b;
            c=c*(x(k)-x0(j));
            ac=a*c;
        end
       
        yy0=yy0+ac;
        end
    yy(k)=yy0;
    
    
end