clear all
clc


x=[-1 1 2];
y=[-3 0 4];
xx=0;

[P] = MetodoDiLagrangef(x,y,xx)

function [P] = MetodoDiLagrangef(x,y,xx)
%metodo di lagrange per approssimazione polinomiale

n=length(x)-1;
P=xx-xx;

for j=0:n
    num=1;
    den=1;
    for i=[0:j-1,j+1:n]
        num=num.*(xx-x(i+1));
        den=den.*(x(j+1)-x(i+1));
    end
 
    P=P + y(j+1).*num./den;
end
end