%Script file to look at the maximum error:
k=5;   %Number of data points
n=k-1; %Degree of polynomial to use

x=[-1 -1/2 0 1/2 1];
f=inline('exp(x)');
y=f(x);

%Construct the degree 4 polynomial and plot the results:
coefs=newtdd(x,y);
cx=linspace(min(x),max(x));
cy=nest(n,coefs,cx,x);
ty=f(cx);

plot(x,y,'k*',cx,cy);

%Look at the error:
P=inline('(exp(1)/factorial(5))*(x+1).*(x+1/2).*x.*(x-1/2).*(x-1)');
cf=P(cx);

figure(2)
plot(cx,cf,'k-',cx,ty-cy,'b-');
title('Maximum error (black) and actual error (blue)');