Matlab Plot
 stem
In this example, we study the 'stem'
instruction to plot Matlab
functions.
It draws vertical lines (with a
little circle at the tip)
proportional to
the value of the function at that particular horizontal value. 'stem' does not
join
the circles with a line, and it is very helpful to stress the fact that
the
function is
not
continuous but discrete.
Let's assume that we want to plot the following elegant exponential and
sinusoidal function:
Example:
let's draw a simple discrete function
We can develop a script like this:
%
Avoid superimposed operations and close previous figs.
clc;
clear; close all
%
First, we define 51 values of our independent variable
x = 0 :
2*pi/50 : 2*pi;
%
Second, we define the function to graph
y =
exp(x/3) .* sin(x);
%
Third, we use the 'stem' function to plot discrete values
stem(x,y)
%
We can add title and labels (as strings in arguments)
title('Demonstration
of the stem function')
xlabel('angle
x')
ylabel('f(x)')
And we get the following plot:
If we define our independant variable using less points, as in
x = 0 :
2*pi/20 : 2*pi;
we get the following visual change:
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'Matlab Plot' to
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'Matlab
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