Square Matrix :
Any matrix that has equal number of rows and columns is called square matrix. E.g: 2x2, 3x3 matrix.
| 2x2 Square Matrix|| 3x3 Square Matrix|
2 rows & 2 columns
3 rows & 3 columns
Diagonal Matrix :
A Diagonal matrix is a square matrix with numbers on the leading diagonal and zeros in all other places.
Identity Matrix :
An identity matrix is a square matrix denoted as I. It has ones (1) down the leading diagonal and zeros in all other places.
| 2x2 identity|| 3x3 identity|
Note: Any matrix multiplied by its identity matrix leaves the matrix unchanged.
It is similar to multiplying a number by 1.
i.e AI = A (where A is a matrix)
Zero (Null) Matrix :
A zero or null matrix is a matrix with 0 as the element for all its cells (rows and columns).
Symmetric Matrix :
A symmetric matrix is a matrix where aij = aji. i.e an element at the ith row, jth columns should be equal to the element at the jth row, ith columns.
Equality Matrix :
For any two matrices to be said as equal matrices they should be of same size and have same values.