Interduction to MATLAB

•Manal AlotaibiMathematics departmentCollege of science King saud university

Content

MATLAB

What is MATLAB?The MATLAB desktop invironment.MATLAB as calculator.Variables.AlgorithmInterduction to m-file function.

Outline

MATLAB

What is MATLAB?The MATLAB desktop invironment.MATLAB as calculator.Variables.AlgorithmInterduction to m-file function.

• MATLAB is a mathematical and graphical software package with numerical, graphical and programming capabilities.

• it has built-in functions to perform many operations.

MATLAB

Outline What is MATLAB?The MATLAB desktop invironment.MATLAB as calculator.Variables.AlgorithmInterduction to m-file function.

MATLAB

MATLAB

Command window: Type your instructions here and press

ENTER to execute them.

MATLAB

Example: Declare a column matrix withvalues 1,2 and 3.

MATLAB

Command history: a list of instructions executed by MATLAB is shown here .

MATLAB

Workspace: shows a list of variables created by MATLAB.

As you can see, the value of ‘aaa’is shown .

MATLAB

Another way to create a variable Is to press this button .

MATLAB

MATLAB will prompt you to enter the variable name .

MATLAB

As you can see, the variable name has been changed to bbb .

MATLAB

To assign a value to bbb, you can do it intwo ways: 1) Using the command window.

2 )Or by double clicking on bbb .

MATLAB

To clear all variables from memory and close all

figures, use the clear, close all command.

MATLAB

As you can see, all workspace variables are deleted when you execute this command.

MATLAB

To clear the command window,use the clc (clear console) command.

MATLAB

As you can see, all console entries are deleted when

you execute this command.

MATLAB

If you want to see help,you can type help at the

command window.

MATLAB

Outline

What is MATLAB?The MATLAB desktop invironment.MATLAB as calculator.Variables.AlgorithmInterduction to m-file function.

MATLAB

Operators

•addition + a+b•subtraction-a-b•multiplication*a*b•Division(left) / a/b•Division(right)\ a\b (ba)•power^a^b

MATLAB

Operator precedence rules

1. () parentheses.2. ^ power.3. - negation.4. */ \ all multiplication and division.5. + - addition and subtraction.

MATLAB

Examples >>6*5

ans= •30 >>17/5

ans= 3.4000

>>ansans=

3.4000

>>6*5ans= •30 >>17/5

ans= 3.4000

>>ansans=

3.4000

>> x=6*5x=

30>> y=17/5;>> yy=

3.4000>> z=x+yz=

33.4000>> whoYour variables are:x y z

>> x=6*5x=

30>> y=17/5;>> yy=

3.4000>> z=x+yz=

33.4000>> whoYour variables are:x y z

MATLAB

Some functions in MATLAB• exp(x) ex

• sin(x) sin x• asin(x) sin-1x• log(x) ln x• log10(x) log x• sqrt(x)• abs(x) |x|• sum(x) ix

• pi p• i,j imaginary unit• NaN Not-a-Number• Inf

MATLAB

Example

y x>>y=x^0.5;>>y=x^(1/2);>>y=sqrt(x);

MATLAB

Outline

What is MATLAB?The MATLAB desktop invironment.MATLAB as calculator.Variables.AlgorithmInterduction to m-file .

MATLAB

Variables Creating Variables:

– Names • Can be any string of upper and lower case letters along with numbers

and underscores but it must begin with a letter• Reserved names are IF, WHILE, ELSE, END, SUM, etc.• Names are case sensitive

– Value• This is the data the is associated to the variable; the data is accessed by

using the name.– Variables have the type of the last thing assigned to them• Re-assignment is done silently – there are no warnings if you overwrite

a variable with something of a different type.

MATLAB

Outline

What is MATLAB?The MATLAB desktop invironment.MATLAB as calculator.Variables.AlgorithmInterduction to m-file

MATLAB

Definition of algorithm

• An algorithm is the sequence of steps needed to solve a problem.

MATLAB

Outline

What is MATLAB?The MATLAB desktop invironment.MATLAB as calculator.Variables.AlgorithmInterduction to m-file .

MATLAB

To create an m-file, 1) type edit at the command window, or

2 )Press this button.

MATLAB

The previous command willdisplay the editor window.

The editor creates an m-filethat can be used to write

your MATLAB programs .

MATLAB

To execute a program, pressthe RUN button.

MATLAB

End the first part