This is a line of numbers that runs diagonally from the top left-hand corner to the bottom right-hand corner for the

matrix with equal numbers of rows and columns (i.e. a square matrix). Consider the matrix below.

This matrix has the same number of rows and columns. It is a 3 3 matrix. Its leading diagonal is what has been enclosed in the loop below.

1. Minor diagonal
This is a line of numbers that runs diagonally from the bottom lefthand corner to the top right-hand corner. For the matrix above its minor diagonal is what has been enclosed in the loop.

1, 5 and 3 are the entries of the minor diagonal.

Types of matrices

1. Column matrix
This is a matrix with only one column. E.g.

2. Row matrix
This is a matrix with only one row. E.g. c = (0 ,4)

1. Zero matrix
This is a matrix whose all of its elements are zeros. E.g.
1. Equal matrix
Two or more matrices are equal if and only if their corresponding elements are equal and are of same order.
Example.

Given

is equal to mattrix B, then

a =4, b= 10

c =6 , d=-4

1. Square matrix
This is a matrix with equal number of rows and columns. E.g.
1. Identity matrix
This is a square matrix with 1 as an element in the leading (major) diagonal and zeros elsewhere. At times, it is known as unit matrix and it is denoted by the letter I. Some few examples of identity matrix include the following:

Example

1. Three sales girls sold the following number of bottles of lotion on a certain day.
Liz sold 9 bottles of Dear heart, 13 of Razac and 6 of Venus.
Suzi sold 8 bottles of Movit lotion, 7 of Razac and 10 of Venus.
Aber sold 15 bottles of Movit lotion, 1 of Dear heart and 18 of Razac.
Show this information in a 3×4 matrix.
Solution
1. The table below shows the number of times that three couples attended various types of entertainment in one year.

a) Write down the information in the table in the form of a matrix and state the order of the matrix

b) Write the Frank’s attendance as a column matrix. What is the order ofthis matrix?

c) Write as a row matrix, the number of times the plays have been attended, and state the order of the matrix.

c = (8,1) = The order is 1 X 3