lagrange

%A = [-2 -1 0 2]
%B = [0 1 1 2]
function [g] = Lagrang(X,Y)
lx = length(X);
ly = length(Y);
if(lx ~= ly)
    disp('Podaj tablice o takich samych wymiarach')
    return
end
g = 0;
syms x;
for j = 1: lx
v = 1;

for i = 1 : lx
    if(i~=j)
    v = v*(x-X(i))/(X(j)-X(i));
    end
end
v=v*Y(j);
g = g+v;
end
g = simplify(g);
z = X(1):0.1:X(lx)+1;
f = @(x)eval(g);
hold on
grid on;
plot(z,f(z),X,Y,'v')
hold off