MATLAB: Is plot(x,y=0) not giving a line at y=0

MATLABplot

I am trying to plot a function with a line through y=0 too.
I wrote this code:
x=0:0.01:10*pi;
plot(x,2*sin(x).*exp(-x/4));
hold on
y=0;
plot(x,y)
This is only giving me a curve and no line through y=0.
I am getting the y=0 line with this code:
x=0:0.01:10*pi;
plot(x,2*sin(x).*exp(-x/4));
hold on
y=zeros(length(x));
plot(x,y)
So what is happening with the pervios code? Doesnt y=0; make any sense here?

Best Answer

Stephen’s answer is the way I would do it but the explanation for the not satisfactory result of your code:
y=0;
You create a scalar and you try to plot it with x which is vector, it doesn't work like that in MATLAB you should have done
plot(x,zeros(size(x))) % this creates zeros as same size as x.
Related Question