Saturday, May 24, 2025

MATRICES: WHAT THEY ARE AND WHY THEY MATTER

Introduction

Matrices are fundamental objects in linear algebra. But after all — what is a matrix?

What is a matrix?


A matrix is a rectangular array of numbers arranged in rows and columns. If the matrix has m rows and n columns, we say it is a matrix of order m × n (read: 'm by n'). Matrices are usually denoted by uppercase bold letters, like A, B, or M.

General form


A general matrix looks like this:

              Examples of matrices


     1.     A 4×4 matrix:                            

2. A 2 x3 matrix:        

                

When are matrices useful?

Matrices are essential for:


         🔹 Solving systems of linear equations
         🔹 Representing data in statistics and machine learning
         🔹Describing transformations in geometry
         🔹Working with equations in economics, physics, and engineering

Common types of matrices


🔺 Square matrix: a matrix with the same number of rows and columns (n × n).

                                   

🔺Row matrix: a matrix with only one row (1 × n).

                                  

🔺 Column matrix: a matrix with only one column (m × 1).

                                      

🔺Zero matrix: a matrix in which all elements are zero.    

 

             

🔺Identity matrix: a square matrix with 1’s on the main diagonal and 0’s elsewhere.

                                           

🔺 Diagonal matrix: a square matrix where all non-diagonal elements are zero.     

                

🔺Symmetric matrix: a square matrix that is equal to its transpose.    

                               

🔺 Transpose of a matrix: a matrix obtained by switching rows and columns.

                                                                                           

Conclusion


A matrix is more than just a table of numbers — it's a structured tool that helps organize and operate on data efficiently. Now that you know what a matrix is, you're ready to explore operations involving matrices and their properties.

📘 Next post: Matrix operations — how to add, subtract, and multiply matrices.

 

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