This document provides an overview of matrices. It defines a matrix as a rectangular array of elements and notes they can contain integers, real numbers, or other matrices. It explains how to specify the order of matrices based on their rows and columns. The document also covers basic matrix operations like scalar multiplication and addition/subtraction. Additionally, it defines special types of matrices including row matrices, column matrices, square matrices, and distance matrices. The overall objectives are to understand what matrices are, how to perform basic operations on them, and recognize special matrix forms.
2. Slide number 2
Matrices lesson 1 objectives
• After this lesson you should have a clear
understanding of:
• What matrices are;
• Performing basic operations on matrices;
• Special forms of matrices
3. Slide number 3
What is a matrix?
• A matrix is a rectangular array of elements
• The elements may be of any type (e.g. integer,
real, complex, logical, or even other matrices).
• In this course we will only consider matrices
that have integer or real number values.
−5 0 1 2
3 −4 −9 2
3 1 4 2
6. Slide number 6
Specifying matrix elements
• aij denotes the
element of the
matrix A on the ith
row and jth
column.
A=
column j →
row i
↓
−5 0 1
2 3 −4
−9 2 6
3 1 4
• a12 = 0
• a21 = 2
• a23 = -4
• a32 = 2
• a41 = 3
• a43 = 4
7. Slide number 7
Matrix operations: scalar multiplication
• Multiplying an m × n matrix by a scalar results in an m × n
matrix with each of its elements multiplied by the scalar.
• e.g.
−−−
−−
−−
−
=
−
−
−
−
−
−
−
=
−
−
−
826
12418
864
2010
413
629
432
105
2
1239
18627
1296
3015
413
629
432
105
3
8. Slide number 8
Matrix operations: addition…
• Adding or subtracting an m × n matrix by an m × n matrix
results in an m × n matrix with each of its elements added or
subtracted.
• e.g.
−
−
−
−−−
=
−
−
−−
−
−
−
−
−
−
−
−
=
−
−
−−
+
−
−
−
431
8112
113
136
024
213
541
231
413
629
432
105
417
436
971
334
024
213
541
231
413
629
432
105
9. Slide number 9
…Matrix operations: addition
• Note that matrices being added or subtracted
must be of the same order.
• e.g.
invalid!
113
201
413
629
432
105
=
−
+
−
−
−
10. Slide number 10
Special matrices: row and column
• A 1 × n matrix is called a row matrix.
e.g.
• An m × 1 matrix is called a column matrix.
e.g. 1 columns→
3 rows
↓
3
−1
5
6 columns→
1 rows
↓
2 1 1 −2 1 −5[ ]
11. Slide number 11
Special matrices: square
• An n × n matrix is called a square matrix.
i.e. a square matrix has the same number of
rows and columns.
e.g.
[ ]
−−
−−
−−
−
4705
7350
0523
5031
211
010
210
21
32
1
12. Slide number 12
Special matrices: distance
• A distance matrix is a square matrix that
shows the distances between locations.
Distance matrices are frequently used on road
maps to show the number of kilometres
between major cities. Note that the
main diagonal elements are all zeros.
13. Slide number 13
Matrices lesson 1 objectives
• After this lesson you should have a clear
understanding of:
• What matrices are;
• Performing basic operations on matrices;
• Special forms of matrices;