Matrices in MATLAB

1. MATLAB
Developed by
Pranoti R. Doke
Date:
1
Chapter 6
(Matrices)

2. Matrices:
2
>>> A=[1 2 3;4 5 6;7 8 9]
A =
1 2 3
4 5 6
7 8 9
>>>

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


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


987
654
321
Generation of matrices :
Columns separated by space or a comma Rows separated by semi-colon

3. Matrices :
3
1. Concatenation:
b = [a 10*a ; -a [1 0 0 ; 0 1 0 ; 0 0 1]]
b =
1 2 3 10 20 3 0
4 5 6 40 50 60
7 8 9 70 80 90
-1 -2 -3 1 0 0
-4 -5 -6 0 1 0
-7 -8 -9 0 0 1
2. Replicate :
>> a = [1 2 ; 3 4]
a =
1 2
3 4
>> repmat(a,2,3)
ans =
1 2 1 2 1 2
3 4 3 4 3 4
1 2 1 2 1 2
3 4 3 4 3 4

4. Matrices :
4
Arithmatic operations in MATLAB :
>>A= [1 2 3 ; 4 5 6 ; 7 8 9]
A =
1 2 3
4 5 6
7 8 9
>> B= [1 1 1 ; 2 2 2 ; 3 3 3]
B =
1 1 1
2 2 2
3 3 3
A*B
A.*B
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333
222
111
987
654
321

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3x93x83x7
2x62x52x4
1x31x21x1

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272421
12108
321
=
=
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505050
323232
141414

5. 1/8 …
5
A.^ B
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729512343
362516
321
=
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
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333
222
111
987
654
321
A ^ B
Error using ==> ^
Either A or B must be scalar

6. 2/8…
6
> > a [ a(a)]
ans =
1 2 3 1 4 7
4 5 6 2 5 8
7 8 9 3 6 9
> a = [ [ 1 2 3 ] ’ [ 4 5 6 ] ’]
= 1 4
2 5
3 6
Deleting a row from matrix:
> > a(: , 2 ) = [ ]
a =
1 3
4 6
7 9

7. Examples to solve :
7
Q). Given Matrix is ,
A=[ 1 5 9 10; 13 15 2 5 ; 4 8 6 9 ] find out its
i. Replication of A
ii. Concatenation for [ A 5*A ; A/2 A+2 ]
iii. Transpose of A
Q). Solve for
A=[ 2 3 6 ; 4 6 9 ; 8 4 10 ; 1 5 11 ]
Caculate all arithmatic operations in MATLAB for above matrix .
Q). Determine the value of the expression a(b + c(c + d))a, where
a = 2, b = 3, c = −4 and d = −3.