数值计算方法Matlab实验

%lagrange insert function y=lagrange(x0,y0,x) clc; clear; a=-1; b=1; n0=[2,3,7,10]; for f=1:4 for l=1:n0(f)+1 x0(l)=(b+a)/2+((b-a)/2)*cos((2*l-1)*pi/(2*(n0(f)+1))); y0(l)=1/(1+25*x0(l)^2); x=linspace(-1,1,101); y1=1./(1+25.*x.^2); n=length(x0); m=length(x); for i=1:m z=x(i); s=0.0; for k=1:n p=1.0; for j=1:n if j~=k p=p*(z-x0(j))/(x0(k)-x0(j)); end end s=p*y0(k)+s; end y(i)=s; end end c=n0(f); subplot(2,2,f) plot(x,y,'--k',x,y1,'-k','LineWidth',1.3); title([num2str(c),'次切比雪夫插值 ']) end