x=[-6:0.01:6];
n=size(x,2);
y=zeros(n,1);
for i=1:n
  if x(i)==0
    y(i)=1;
  else
    y(i)=sin(pi*x(i))/(pi*x(i));
  end;
end;
plot(x,y,'black');
axis([-6 6 -0.5 1.5]);
axis on;
