%newton alle differenze
clear all
close all
clc

x=linspace(0.5,1.5)
f=@(x) 1./sqrt(x) -1;
Nmax=200;
tol=sqrt(eps);

[c] = NDIFF(f,x,Nmax,tol)
fplot(f)
xline(c)

function [x0] = NDIFF(f,x,Nmax,tol)
x0=x(1);
k=1;
e(k)=abs(f(x0));

while k<Nmax && e(k)>tol
    if x0==0
        h = sqrt(eps);
    else 
        h= sqrt(eps)*x0;
    end
    l = (f(x0+h) - f(x0))/(h);
    x0= x0 - f(x0)/l;
    k=k+1;
    e(k)=abs(f(x0));

end
end