1
©2009 by L. Lagerstrom
Introduction to Matlab
• Numbers
• Operators
• The Command Window
• Chaining operations
• Syntax errors
• Precedence of operations
• Variables and assignment statements
• Mathematical functions
• Punctuation: semicolons, commas, and ellipses
©2009 by L. Lagerstrom
Numbers in Matlab
•
Numbers in Matlab may be entered in either fixed point or
floating point format.
•
Fixed point examples: 2.639, 827, 0.000023.
•
Floating point examples: 4.39e5, 4.39E5, 245.8e2. Note that
"e" or "E" here stands for powerof10 exponent and does NOT
refer to the exponential function e
x
. In other words, 4.39e5 in
Matlab means (4.39)(10
5
) in regular math notation. Remember
also that we call the 4.39 part the "mantissa." (We'll learn how
to use the exponential function a little later.)
©2009 by L. Lagerstrom
Math Operators
Matlab has the usual math operators:
• Addition: 5 + 8
• Subtraction: 9  4
• Multiplication: 5*7 (i.e., an asterisk)
• Division: 56/8 (i.e., a slash)
• Exponentiation: 7^2 (i.e., a caret symbol; note that 7^2 is 7
squared)
In addition to the regular / operator for division, there is also a \
(backslash) operator, called the "left division" operator. (And the
regular / operator is the "right division" operator.) When we write
8\56 it means "8 divided into 56." That is, 8\56 is the same as
56/8. (The reason for the left division operator will become clear
when we cover solving systems of linear equations.)
©2009 by L. Lagerstrom
The Matlab Command Window
When you start Matlab, the first window you will usually see is the
"Command Window" with a ">>" prompt. You may enter math
expressions at the prompt and then press the Enter key to have
Matlab execute them. The results will be displayed as shown
below. (The "ans" stands for "answer.") Examples:
>>5 + 8
ans =
13
>>3*7
ans =
21
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document2
©2009 by L. Lagerstrom
Interpreting Our Examples
It's very important to understand what's going on in an example
like that below, so that you don't get confused with our later
examples. The ">>5 + 8" line means that we have typed "5 + 8" at
the >> prompt in the Matlab Command window. (Sometimes we
just call it the "command prompt".) We then press the Enter key to
enter that expression, causing Matlab to execute it. After it
executes it, Matlab displays the result (the "ans = 13" part).
>>5 + 8
ans =
13
©2009 by L. Lagerstrom
A Note re. Decimal Places
Later we will cover in detail how Matlab displays numbers
regarding number of decimal places, etc. For now, just understand
that if the result is an exact integer, then it is displayed as such
with no decimal part. If it's not an exact integer, then the decimal
part is displayed up to four decimal places, rounded appropriately.
(This is known as "format short.")
This is the end of the preview.
Sign up
to
access the rest of the document.
 Spring '10
 Lagerstrom
 Imperative programming, L. Lagerstrom

Click to edit the document details