Chapter 2: Plotting in MATLAB

Before we plot a graph on matlab we should specify what will be our x axis and our y axis. For instance, we could let x be the independent variable and y is a function of x.

                If we want to plot a cosine function we could type:

>> t = 0:0.001:5;            %this means, the first number 0 is the initial value and 5 is the last value,

                                     %the 0.001 is the increment of the cosine function,

                                     %NOTE: make sure to put a semi-colon after every syntax

>>y = cos(t-0.25);           %our function;

>>plot(t,y,’r’)                   %plot syntax; ‘r’ means the color of the line is red

You should have a graph like this:

We could also put title, label on our graph:

>>title(‘Cosine plot’)

>>xlabel(‘time’)

>>ylabel(‘Amplitude’)

That’s it for plotting graph..you could place two or more graphs in one figure.

Note: Try exploring the syntax ‘subplot’. Without the quotes. You could also try changing the values of t, comment your exploration here. It is much appreciated. Thanks! Up next.. Simulink Basics