Interduction to MATLAB Manal Alotaibi Mathematics department College

Interduction to MATLAB • Manal Alotaibi Mathematics department College of science King saud university

Content q. What is MATLAB? q. The MATLAB desktop invironment. q. MATLAB as calculator. q. Variables. q. Algorithm q. Interduction to m-file function. MATLAB

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

• 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 q What is MATLAB? q The MATLAB desktop invironment. q MATLAB as calculator. q Variables. q Algorithm q Interduction to m-file function. MATLAB

MATLAB

Command window: Type your instructions here and press ENTER to execute them. MATLAB

Example: Declare a column matrix with values 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

2) Or by double clicking on bbb. To assign a value to bbb, you can do it in two ways: 1) Using the command window. 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 q What is MATLAB? q The MATLAB desktop invironment. q MATLAB as calculator. q Variables. q Algorithm q Interduction to m-file function. MATLAB

Operators addition + a+b subtraction-a-b multiplication*a*b Division(left) / a/b Division(right) ab (b a) power^a^b MATLAB • • •

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

Examples >> 6*5 ans = 30 • >> 17/5 ans = 3. 4000 >> ans = 3. 4000 MATLAB >> x=6*5 x= 30 >> y=17/5; >> y y= 3. 4000 >> z=x+y z= 33. 4000 >> who Your variables are: x y z

Some functions in MATLAB • • exp(x) sin(x) asin(x) log 10(x) sqrt(x) abs(x) sum(x) MATLAB ex sin-1 x ln x log x |x| • • pi i, j Na. N Inf p imaginary unit Not-a-Number

Example >>y=x^0. 5; >>y=x^(1/2); >>y=sqrt(x); MATLAB

Outline q. What is MATLAB? q. The MATLAB desktop invironment. q. MATLAB as calculator. q. Variables. q. Algorithm q. Interduction 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