BIL108E : Introduction to the Scientific and Engineering Computing with
MATLAB
CRN
: 23610
LECTURE NOTES – 1
INTRODUCTION TO MATLAB
The name MATLAB stands for MATrix LABoratory. MATLAB is a highperformance language for technical computing. It integrates computation,
visualization, and programming environment. Furthermore, MATLAB is a
modern programming language environment: it has sophisticated data
structures, contains built-in editing and debugging tools, and supports objectoriented programming. These factors make MATLAB an excellent tool for
teaching and research.
MATLAB is a computer program that can be very helpful in solving the sorts of
mathematical problems you will frequently encounter throughout your
engineering or technology coursework.
MATLAB’s built-in features can be used to solve a wide variety of numerical
problems, from the very basic, such as a system of 2 equations with 2 unknowns
to the more complex, such as
Factoring polynomials,
Fitting curves to data points,
Making calculations using matrices,
Performing signal processing operations such as Fourier transforms,
Building and training neural networks.
Starting And Quitting
 WINDOWS
Start: click Matlab icon
Stop: File/Exit Matlab
 Command Line
Type: matlab
If MATLAB is successfully invoked, prompt becomes ">>".
Type: quit
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Figure 1. MATLAB workspace (Houcque,2005)
Customization
MATLAB allows you to personalize the workspace.
To do so; “File  Preferences”
Conversing MATLAB
who
MATLAB replies with the variables in your workspace
what
MATLAB replies with the current directory and MATLAB files in the directory
help
The most important function for learning MATLAB on your own
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CREATING MATLAB VARIABLES
Defining MATLAB variables is a simple procedure. MATLAB variables are created
with an assignment statement.
variable name = a value (or an expression)
To create a variable, simply assign a value to a name:
>>var1=3.14
>>myString=‘hello world’
For example,
>> x = expression
where expression is a combination of numerical values, mathematical operators,
variables, and function calls. On other words, expression can involve:
• manual entry
• built-in functions
• user-defined functions
Following rules need to be considered while assigning a variable;



First character must be a letter
After that, any combination of letters and numbers or “_” can be used
Case sensitive, so that Var1 and var1 different from each other
Built-In Variables
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Figure 2. Some Built-In Variable examples for MATLAB
SYNTAX
 A scalar is simply just a fancy word for a number (a single value (1*1)).
 A variable can be given a value explicitly
>>a = 85
shows up in workspace!
 Or as a function of explicit values and existing variables
>>c = 1.6*47-2*a
 To suppress output, end the line with a semicolon
»cool= 18/5;
 A vector is an ordered list of numbers (one-dimensional). In MATLAB
they can be represented as a row-vector or a column-vector (1*n) or
(n*1).
 Row vector: comma or space separated values between brackets
>>row = [1 2 5.4 -6.6];
>>row = [1, 2, 5.4, -6.6];
 Column vector: semicolon separated values between brackets
>>column = [4;2;7;4];
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Figure 3. Display of row and column vector

A matrix is a rectangular array of numbers (multidimensional).In
MATLAB, a two-dimensional matrix is defined by its number of rows and
columns (n*m) or (m*n).
Figure 4. Matrix Formation
SAVE/CLEAR/LOAD
 Use save to save variables to a file
>>save myfile a b
 saves variables a and b to the file myfile.mat
 myfile.mat file in the current directory
 Default working directory is
>>\MATLAB\work
 Use clear to remove variables from environment
>>clear a b
 look at workspace, the variables a and b are gone
 Use load to load variable bindings into the environment
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>>load myfile
OPERATORS
MATLAB allows arithmetic operations: +, −, ∗, and ˆ to be carried out on matrices.
Thus,
A+B or B+A
A*B
A^2
α*A or A*α
is valid if A and B are of the same size
is valid if A’s number of column equals B’s number of rows
is valid if A is square and equals A*A
multiplies each element of A by α
On the other hand, array arithmetic operations or array operations for short, are
done element-by-element. The period character, ., distinguishes the array
operations from the matrix operations. However, since the matrix and array
operations are the same for addition (+) and subtraction (−), the character pairs
(.+) and (.−) are not used. The list of array operators is shown below in Table 3.2.
If A and B are two matrices of the same size with elements A = [aij] and B = [bij],
then the command
.*
./
.^
Element-by-element multiplication
Element-by-element division
Element-by-element exponentiation
Table 1. Array Operators
To simplify, let’s consider two vectors U and V with elements U = [ui] and V = [vj].
U. ∗ V
produces
[u1v1 u2v2 . . . unvn]
U./V
produces
[u1/v1 u2/v2 . . . un/vn]
U.ˆV
produces
[u1v1 u2v2 . . . unvn ]
BUILT-IN FUNCTIONS
MATLAB offers many predefined mathematical functions for technical
computing which contains a large set of mathematical functions.
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Table 2. Elementary Functions
GETTING HELP
 Use on-line help to request info on a specific function
>> help sqrt
 In the current version (MATLAB version 7), the doc function opens the
on-line version of the help manual. This is very helpful for more complex
commands.
>> doc plot
 Use “lookfor” to find functions by keywords. The general form is
>> lookfor FunctionName
MATLAB FILES
 The Workspace can be saved to a data file
extension is .mat (ex: hello.mat)
binary form
.mat files can be reloaded by using open from file menu
 MATLAB offers a wealth of built-in math functions that can be quite
helpful for many computational problems
 Elementary MATLAB functions (help elfun)
Trigonometric functions
Exponential functions
Complex functions
Rounding and remainder functions
 Specialized MATLAB functions (help specfun)
Specialized math functions
Number theoretic functions
Coordinate transformations
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