f1.m

该算法实现了拉格朗日插值并比较了龙格现象

x=[-5:1:5];
y=1./(1+x.^2);
%u = -4.5:0.5:4.5; 
%v = polyinterp(x,y,u);
%plot(x,y,'o',u,v,'-');
plot(x,y,'-');
x0=[-5:0.1:5];
y0=lagrange(x,y,x0);
y1=1./(1+x0.^2);
%plot(x0,y0,'o',u,v,'--r')
plot(x0,y0,'--r')
hold on
plot(x0,y1,'-b')
%plot(x0,y1,'@',u,v,'-b')
legend('拉格朗日插值曲线','原曲线')