Unitstep Function (Heaviside Function) Plotting Help

I am working with Matlab and I am trying to create a unitstep function using the heavistep function. My code is shown below.

%f(x) = 0 for x<0 and f(x) = 1 for x>=1

function unit = unitstep(t)

unit = heaviside(t);

After creating this file I used the following commands in the command window.

t = -20:0.001:20;

plot (unitstep(t));

When I plot the unitstep function I created I get the below image. My question is why does the graph rise to y = 1 at x = 2 instead of at x = 0?

My plot.

Expected Output plot

Answer 1

[Star Strider]

There appears to be missing information, specifically because in the top plot it is not rising at , it is instead rising at .

This produces the desired result:

unitstep = @(t) t>0;

t = -20:0.001:20;

figure
plot(t, unitstep(t))
axis([min(t)-0.1  max(t)+0.1    -0.1  1.1])
grid

.