MATLAB: How to display y=0 in figure

how to display y=0 in figure

Hi,
I want to display like the figure.
How to display (y=0) like this.

Best Answer

r=[0.1:0.1:10];
y = zeros(length(r),1);
epsilo=0.008909;
sigma=3.326;
E=4*0.008909*(sigma^12./r.^12-sigma^6./r.^6)*1000;
plot(r,E,'r');hold on;
plot(r,y,'b');