x = [0 1 2];
f = 1./(1+x);

t=divdiff(x,f);


x = [0, 1, 2];
f = 1./(1+x);
df = (-1)./((1+x).^2);

[z,t]=divdiff2(x,f,df)



x=linspace(1,2,11);
f=1./(1+x);
df = (-1)./((1+x).^2);
t=divdiff(x,f)
[z,t]=divdiff2(x,f,df)

x = [-2, -1, 0, 1, 2, 3, 4];
f = [-5, 1, 1, 1,7 ,25, 60];

t=divdiff(x,f)

x = [-2, -1, 0, 1, 2, 3, 4];
f = [-5, 1, 1, 1,7 ,25, 60];

t=forwarddiff(f)
t=backdiff(f)