三次样条插值matlab语句

%三次样条插值symsxf1=1/(1+x^2);f2=1/(1+5*x^2);%定义符号变量x=-5:5;y1=subs(f1,x);y2=subs(f2,x);%取插值点xx=-5:0.25:5;yy=spline(x,y1,xx);yy2=spline(x,y2,xx);%获得插值数据subplot(2,2,1)plot(x,y1,'o',xx,yy),grid%画出插值基点与插值结果t=-5:0.05:5;yt=subs(f1,t);yt2=subs(f2,t);subplot(2,2,2)plot(t,yt),grid%画出原函数图像subplot(2,2,3)plot(x,y2,'o',xx,yy2),grid%画出插值基点与插值结果subplot(2,2,4)plot(t,yt2),grid%画出原函数图像结果如下图所示：