How to Use MATLAB A Brief Introduction

                                   Some Useful Commands:

• help                         % list all the topics
• clear                        % remove all the data in current session
• ; (semicolon)          % prevent commands from outputing results
• % (percent sign)     % comments line
• clc                           % clears the screen

Vectors:

A row vector in MATLAB can be created by an explicit list, starting with a left bracket,

entering the values separated by spaces (or commas) and closing the vector with a right

bracket.

• A column vector can be created the same way, and the rows are separated by semicolons.
• Example:

>> x = [ 0 0.25*pi 0.5*pi 0.75*pi pi ]

x = x is a row vector.

0 0.7854 1.5708 2.3562 3.1416

>> y = [ 0; 0.25*pi; 0.5*pi; 0.75*pi; pi ]

y = y is a column vector.

0

0.7854

1.5708

2.3562

3.1416

• Vector Addressing – A vector element is addressed in MATLAB with an integer

index enclosed in parentheses.

• Example:

>> x(3)

ans =

1.5708 ( 3rd element of vector x)

• The colon notation may be used to address a block of elements.

(start : increment : end)

start is the starting index, increment is the amount to add to each successive index, and end

is the ending index. A shortened format (start : end) may be used if increment is 1.

• Example:
• >> x(1:3)
• ans =
• 0 0.7854 1.5708  (1st to 3rd elements of vector x)
• NOTE: MATLAB index starts at 1. 

                                                    Some useful commands:

• x = start:end                                 create row vector x starting with start, counting by one,                                                                ending at end
• x = start:increment:end                create row vector x starting with start, counting by increment,                                                      ending at or before end
• linspace(start,end,number)           create row vector x starting with start, ending at end, having                                                         number elements
• length(x)                                       returns the length of vector x
• y = x’                                            transpose of vector x
• dot (x, y)                                       returns the scalar dot product of the vector x and y.

                                               Array Operations

• Scalar-Array Mathematics

For addition, subtraction, multiplication, and division of an array by a

scalar simply apply the operations to all elements of the array.

• Example:

>> f = [ 1 2; 3 4]

f =

1 2

3 4

>> g = 2*f – 1

g =

1 3

5 7

Each element in the array f is

multiplied by 2, then subtracted

by 1

• Element-by-Element Array-Array Mathematics.

Operation                              Algebraic Form                                MATLAB

Addition                                      a + b                                                  a + b

Subtraction                                  a – b                                                  a – b

Multiplication                              a x b                                                  a .* b

Division                                       a ÷ b                                                  a ./ b

Exponentiation                            a^b                                                     a .^ b