Recap
 Sum and Product Functions
 Matrix Size Function
 Variance and Standard Deviation
 Random Numbers
 Complex Numbers
Computational Limitations
 MATLAB includes functions to identify the largest real
numbers and the largest integers the program can process
Special Values and Functions
Summary of Chapter
 General mathematical functions, such as
 exponential functions
 logarithmic functions
 roots
 Rounding functions
 Functions used in discrete mathematics, such as
 factoring functions
 prime-number functions
 Trigonometric functions, including
 standard trigonometric functions
 inverse trigonometric functions
 hyperbolic trigonometric functions
 trigonometric functions that use degrees instead of radians
Continued….
 Data analysis functions, such as
 maxima and minima
 averages (mean and median)
 sums and products
 sorting
 standard deviation and variance
 Random-number generation for both
 uniform distributions
 Gaussian (normal) distributions
 Functions used with complex numbers
Chapter 5
Plotting
Two-Dimensional Plots
 The most useful plot for engineers is the x–y plot
 A set of ordered pairs is used to identify points on a two-
dimensional graph; the points are then connected by
straight lines
 The values of x and y may be measured or calculated
 Generally, the independent variable is given the name x
and is plotted on the x -axis, and the dependent variable is
given the name y and is plotted on the y -axis
Simple x-y Plots
 Once vectors of x -values and y -values have been




defined, MATLAB makes it easy to create plots
Suppose a set of time versus distance data were obtained
through measurement
We can store the time values in a vector called x and the
distance values in a vector called y :
x = [0:2:18];
y = [0, 0.33, 4.13, 6.29, 6.85, 11.19, 13.19, 13.96, 16.33,
18.17];
Continued….
 To plot these points, use the plot command, with x and y
as arguments:
plot(x,y)
 A graphics window automatically opens, which MATLAB
calls Figure 1
Titles, Labels and Grids
 Good engineering practice requires that we include axis
labels and a title in our plot
 The following commands add a title, x - and y -axis labels,
and a background grid:
 plot(x,y)
 xlabel('Time, sec')
 ylabel('Distance, ft')
 grid on
Continued….
 As with any MATLAB commands, they could also be
combined onto one or two lines, separated by commas:
 plot(x,y) , title('Laboratory Experiment 1')
 xlabel('Time, sec' ), ylabel('Distance, ft'), grid
Multiple Plots
 If you are working in an M-file when you request a plot,
and then you continue with more computations, MATLAB
will generate and display the graphics window and then
return immediately to execute the rest of the commands in
the program
 If you request a second plot, the graph you created will be
overwritten
 There are two possible solutions to this problem:
 Use the pause command to temporarily halt the execution of
your M-file program so that you can examine the figure
 Create a second figure, using the figure function
Continued….
 The pause command stops the program execution until
any key is pressed
 If you want to pause for a specified number of seconds,
use the pause(n) command, which will cause execution to
pause for n seconds before continuing
 The figure command allows you to open a new figure
window
 The next time you request a plot, it will be displayed in
this new window
Continued….
 For example:
figure(2)
opens a window named “Figure 2,” which then becomes
the window used for subsequent plotting
 Executing figure without an input parameter causes a new
window to open, numbered consecutively one up from the
current window
 For example: if the current figure window is named
“Figure 2,” executing figure will cause “Figure 3” to open