This document provides an overview of basic MATLAB commands and functions. It introduces MATLAB as a program for technical computing, describes how to access help documentation and view variable values, and provides examples of basic arithmetic, matrix operations, logical operations, and solving systems of linear equations. Key functions and operations covered include addition, multiplication, matrix multiplication, transposition, comparison operators, and inverting a matrix to solve linear systems.

3. -
Help Variable
-

4. Matlab
Matrix
Laboratory
http://www.mathworks.com/

5. 
command
windows
workspace :
command


history


8. help
>> doc sqrt
>> help sqrt
Help icon.

9. Variable
>> x=1
x=
1
>> x=1;
◦ ans : default variable name for the result
◦ pi:  = 3.1415926…………
◦ Inf or inf : , infinity
◦ NaN or nan: not-a-number
◦ clear.
◦ clear all
◦ clc.




10. >> 3+3
ans =
6
>>14/2
ans =
7
>>13.4-6
ans =
7.4000
>> 14/2 , 5*6 , 1+1.2
ans=
7
ans =
30
ans =
2.2000
------------------------------->>3*2+1
>>3*(2+1)
------------------>> 5+3i
ans =
5.0000 + 3.0000i
>> (3+4i)+(1+i)
ans =
4.0000 + 5.0000i

11. • >>Save mywork.mat
• >>load mywork.mat

12. >> 1/(2+3^2)+4/5*6/7
ans =
0.7766

13. •diag(A)
•Size(A)
•Length(A)

Matrixname(m,n) 
n
m
ones(m,n)
zeros(m,n)
eye(m,n)
the main diagonal

14. Example:
>> f = [ 1 2 3; 4 5 6];
>> h= [ 2 4 6; 1 3 5];
>> f(2,3)
f=
1
ans =
4
6
h=
2
>> h(:,1)
1
ans =
2
1
2
5
3
6
4
3
6
5

15. a=[6 8]/2
a=
3
4
-
a=[1 2;3 4]^2
a=
7 10
15 22
-
a=[1 2] + [3 4]
a=
[4 6]
—
a=[3 4]-[1 2]
a=
[2 2]
-
a=[1 2;3 4]*[3;6]
a=
15
33
-
-

16. a=[1 2;3 4].^2
a=
1
4
9 16
>> a=[1 2 3;4 5 6]'
a=
1
2
3
4
5
6

17. Example:
>> A=[1 2 3;4 5 6];
>> A>3
ans =
0
0
0
1
1
1
>> A<=5
ans =
1
1
1
1
1
0
>> x=[0 0 0 1];
>> x&1
ans =
0
0
0
1
>> x|1
ans =
1
1
1
1

True
1
False
0
AND
&
OR
|
NOT
~

18. 
Example: a system of 3 linear equations
with 3 unknowns (x1, x2, x3):
3x1 + 2x2 + x3 = 10
-x1 + 3x2 + 2x3 = 5
x1 – x2 – x3 = -1
3 2 1
 1 3 2 
A


 1  1  1


 x1 
x 
x   2
 x3 
 
Ax = b
10 
5
b
 
 1
 

19. >> A=[3 2 1;-1 3 2;1 -1 -1];
>> b=[10;5;-1];
>> inv(A)*b
ans =
2.0000
1.0000
2.0000
 x1 
x 
 2
 x3 
 

20. 
A = [3 4 4 3 ; 4 5 6 7 ; 5 6 7 4 ; 4 5 6 7]




