function runge1()
close all
a = -1; b = 1; m = 17; %Equally Spaced, m=17
x = linspace(a,b,m);        y = rung(x,16);
x0 = linspace(-1,1,100);   y0 = rung(x0,16);
[P,S] = polyfit(x,y,17);
pVal = polyval(P,x0);

plot(x,y,'r*',x0,pVal,'g--',x0,y0,'b')
axis([-1,1,-2,2])

function y = rung(x,a)
y = 1./(1+a*x.^2);