Introduction
Matrices
A matrix is a rectangular array or arrangement of entries or elements displayed in rows and columns put within a square bracket [ ].
Matrices are denoted by capital letters [math]A,B,C,...[/math] etc.
General form of a matrix
If a matrix[math]A[/math] has [math]m[/math] rows and [math]n[/math] columns, then it is written as [br][math]A=\left[a_{ij}_{ }\right]_{m\times n},1\le i\le m,1\le j\le n.[/math]
Example of matrices
In a matrix, the horizontal lines of elements are known as rows and the vertical lines of elements are known as columns.
Above matrix [math]A[/math] has [math]2[/math] rows and [math]2[/math] columns, [math]B[/math] has [math]3[/math] rows and [math]3[/math] columns.
Definition
If a matrix [math]A[/math] has [math]m[/math] rows and [math]n[/math] columns then the[b] order or size [/b]of the matrix [math]A[/math] is defined to be [math]m\times n[/math] ( read as [math]m[/math] by [math]n[/math] ).
The order or size of the matrix [math]A[/math] is
The order or size of the matrix [math]B[/math] is
Row, Column, Zero Matrices
Row matrix
A matrix having only one row is called a[b] row matrix[/b]
row matrix of order [math]1\times4[/math].
Column matrix
A matrix having only one column is called a [b]column matrix.[/b]
column matrix of order [math]4\times1[/math].
Zero matrix or Null matrix or Void matrix
A matrix [math]A=\left[a_{ij}\right]_{m\times n}[/math] is said to be a[b] zero matrix or null matrix or void matrix[/b] denoted by [math]O[/math] if [math]a_{ij}[/math] for all values of [math]1\le i\le m[/math] and [math]1\le j\le n.[/math]
zero matrices of order [math]2\times4[/math]
Activity-1
1. multiplication of a matrix by a scalar[br]2. addition and subtraction of two matrices and [br]3. multiplication of two matrices
Activity - Determinants
To every square matrix [math]A=\left[a_{ij}\right][/math] of order [math]n\times n[/math], we can associate a number called the [b]determinant [/b]of the matrix [math]A[/math]
Determinant can be defined only for square matrices.
Determinant of matrix of order 2 by 2.
Quiz -Choose the correct answer
1.The transpose of a rectangular matrix is a[br]
2.The transpose of a row matrix is a[br][br]
3.The transpose of a column matrix is a[br][br]
4.A matrix [math]A[/math] is said to be conformable for multiplication with a matrix [math]B[/math] if[br][br]
5.if [math]det\left(A\right)=0[/math], then [math]A[/math] is called a
6.if, [math]det\left(A\right)\ne0[/math], then [math]A[/math] is called a
7. A matrix having [math]m[/math] rows and [math]n[/math] columns with [math]m\ne n[/math] is said to be a