Hi, at my this post i will show some example of plotting signal on matlab.
First of all i want to give brief explanation.

“MATLAB is a high-level language and interactive environment that enables you to perform computationally
intensive tasks faster than with traditional programming languages such as C, C++, and Fortran. ” (1)

“Key Features

High-level language for technical computing
Development environment for managing code, files, and data
Interactive tools for iterative exploration, design, and problem solving
Mathematical functions for linear algebra, statistics, Fourier analysis, filtering, optimization, and numerical integration
2-D and 3-D graphics functions for visualizing data
Tools for building custom graphical user interfaces
Functions for integrating MATLAB based algorithms with external applications and languages,
such as C, C++, Fortran, Java, COM, and Microsoft® Excel®” (1)

At the beginning i will show you , how to draw a sine function.
1) Plot

x = -pi:0.01:pi; % we made fractions as 0.01 between -pi and pi
figure(1)   %creates figure graphs
plot(x,sin(x)), grid on % draws a continues 2D graph and shows the grid.
title('sine function that between from -pi to pi') % gives a name at just above the graph

figure(2) %creates a second figure graphs
plot(sin(x),'r'), grid on % difference of this, it creates a cont. red graph at values of sin(x).
title('sine function that between from 0 to 629')
xlabel('Radians'); % we can name the axis of graph
ylabel('Magnitude');

Upper code gave us two seperate graphs but if we use subplot command we can show these at same pattern.

x = -pi:0.01:pi; % we made fractions as 0.01 between -pi and pi
figure(1)   %creates figure graphs
subplot(2,1,1);plot(x,sin(x)), grid on % draws a continues 2D graph and shows the grid.
title('sine function that between from -pi to pi') % gives a name at just above the graph
subplot(2,1,2);plot(sin(x),'r'), grid on % difference of this, it creates a cont. red graph at values of sin(x).
title('sine function that between from 0 to 629')
xlabel('Radians'); % we can name the axis of graph
ylabel('Magnitude');

3) Manipulating the graph

As we learned at the signals an systems courses, let’s manipulate the our signal.

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x = 0:0.01:2*pi; % we made fractions as 0.01 between -pi and pi
figure(1)   %creates figure graphs
subplot(2,3,1);plot(x,sin(x)), grid on % my original sin wave.
title('my original sin wave') % gives a name at just above the graph
xlabel('Radians');
ylabel('Magnitude');
subplot(2,3,2);plot(x,sin(x-pi/2)), grid on % signal is shifted by 90 degrees.
title('signal is shifted by 90 degrees')
xlabel('Radians');
ylabel('Magnitude');
subplot(2,3,3);plot(x,2*sin(x)), grid on % Double magnitude.
title('Double magnitude') % gives a name at just above the graph
xlabel('Radians');
ylabel('Magnitude');
subplot(2,3,4);plot(x,(-1*sin(x))), grid on % inversed by horizontal axis.
title('inversed by horizontal axis')
xlabel('Radians');
ylabel('Magnitude');
subplot(2,3,5);plot(-x,sin(x)), grid on % inversed by horizontal axis.
title('inversed by vertical axis') % gives a name at just above the graph
xlabel('Radians');
ylabel('Magnitude');
subplot(2,3,6);plot(x,sin(x),x,cos(x)), grid on % two graphs at same area.
title('two graphs at same area')
xlabel('Radians');
ylabel('Magnitude');

3) Dicrete time signals

We can use ‘stem’ function at this section.

x1= 0:0.2:2*pi;
figure(1);
subplot(4,1,1);plot(x1,sin(x1));
title('Continuous sine wave between zero and 2*pi');
grid on;
subplot(4,1,2);stem(x1,sin(x1));
title('Discrete sine wave between zero and 2*pi');
grid on;
subplot(4,1,3);plot(x1/2,cos(x1));
title('Continuous cosine wave between zero and pi ');
grid on;
subplot(4,1,4);stem(x1/2,cos(x1));
title('Discrete cosine wave between zero and pi ');
grid on;

4) Plotting unit impulse input and unit step input

x1= zeros(1,10);
x1(1)=1;
x2= ones (1,10);
figure(1);
subplot(2,1,1);stem(x1);
title('Unit Impulse response');
subplot(2,1,2);stem(x2);
title('Unit Step Response');

(1)From matlab’s help section.

Regards