In this video we will learn about the topics Matrices, Various types of Matrices ,Representation of Matrices and Order of Matrices

A set of mn numbers (real or imaginary) arranged in the form of rectangular array of m rows and n columns is called an m x n matrix.

Let’s have a look on the example given below:

In the above example, there are 3 rows and 2 columns. So, m =3, n= 2 and we can call it as 3 x 2 matrix

**Summary:**

- A set of mn numbers (real or imaginary) arranged in the form of rectangular array of m rows and n columns is called an m x n matrix.
- [
*a*]_{ij}_{m }_{× 1}is a column matrix. - [
*a*]_{ij}_{1 }_{× n}is a column matrix - In a matrix, A = [
*a*_{ij}*]*_{m × n }, where m represents the number of rows and n represents the number of columns. - m x n is called the order of matrix
- if m≠ n, then the matrix is called as a rectangular matrix
- if m = n, then the matrix is called as a square matrix
**Identity matrix**or**unit matrix**of size*n*is the*n*×*n*square matrix with ones on the main diagonal and zeros elsewhere.

** **

- A square matrix is called
**upper triangular**if all the entries*above*the main diagonal are zero - A square matrix is called
**lower triangular**if all the entries*below*the main diagonal are zero

- Zero or Null matrix : It can be a rectangular matrix or a square matrix
- All the elements of a null matrix are zero

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