octave polyval

x0 = [0 1 2];
y0 = [0 1 0];
w = 3;
p = polyfit(x0,y0,w);
x = -3:0.1:3;
y =polyval(p,x);
plot(x0,y0,'ro',x,y,'b');
title("elo");
xlabel("xd");
ylabel("yd");