Question

What are the rules for multiplying matrices?

Answer 1

The rules for multiplying matrices:

The following are the important rules of matrix multiplication:

1. The number of rows in the first matrix is equal to the number of columns in another matrix
2. The order of the product matrix of $A_{i\times j}$ and $B_{j\times k}$ is $i\times k$.
3. If $AB$ is defined, it is not necessary that $BA$ is also defined.
4. If $A$ and $B$ are square matrices of the same order, then $AB$ and $BA$ are defined.
5. The product of a matrix and identity matrix is the original matrix.
6. If the product of two matrices is a zero matrix, it is not necessary that one of the matrices is a zero matrix.