# Matrix Introduction

## Definition of Matrix

A matrix is a rectangular array of numbers, symbols, or expressions, organized in rows and columns. You will get a complete matrix introduction following all the parts :

• Introduction to matrix algebra

• Introduction to matrices and determinants

• Introduction of eigenvalues and eigenvectors

• Introduction to matrix algebra

All these are introductions to matrices with applications in statistics. So, now at first, it's important to get a brief introduction about matrices.

### Introduction to Matrices

In mathematics, a matrix is also known as matrices. It is a rectangular array of numbers, figures, or expressions, organized in rows and columns. Matrices are usually written in box brackets. In matrices, the horizontal and vertical lines of entries are rows and columns. The size of a matrix is determined by the number of rows and columns that it holds. A matrix with m rows and n columns is named an m × n matrix or M-by-N matrix, while m and n are described its dimensions. The dimensions of the resulting matrix are 2 × 3 up (read “two by three”) as there are 2 rows and 3 columns.

A = $\begin{bmatrix}19 &-20 &13 \end{bmatrix}$

$\begin{bmatrix}1 &5 &-6 \end{bmatrix}$

The individual parts that are the numbers, symbols, or expressions in a matrix are named as their entries.

Given that they are the equivalent size-means having the same number of rows and the equal number of columns), 2 matrices can be plus or minus part by part. The rule for matrix multiplication, though, is that 2 matrices can be multiplied only when the number of columns in the 1st matches the number of rows in the second. Any matrix can be multiplied part-wise by a scalar from its related area.

Matrices that have a singular row are named row vectors, and those which have a single column are described column vectors. A matrix that has an equal number of rows and columns is defined as a square matrix. In some connections, like computer-based algebra programs, it is helpful to study a matrix with no rows or no columns, named an empty matrix.

This was just a small matrix introduction and an intro to matrices. Now let's talk about the different applications of matrices.

Several operations can be used to change matrices like matrix addition, subtraction, and scalar multiplication. These form the basic methods to work with matrices.

These methods can be used in estimating totals, differentiation, and information of products. Take an example of sodas that come in 3 different flavors: lime, orange, and berry, and two different packages: bottle and can. Two tables summing the total sales within last month and this month are recorded to show the amounts. Matrix plus, minus, and scalar multiply can be used to find such things as the sales of the end month and the sales of the present month, the average sales for all flavors, and the packaging of soda in the 2 months.

### Introduction to Matrix Algebra: Addition, Subtraction, and Multiplication

Here, we will go through an introduction to matrices with applications in statistics and basic mathematics.

We use matrices to list information or to represent systems. Because the entries are numbers, we can apply methods on matrices. We plus or minus matrices by adding or subtracting corresponding entries.

To do this, the entries must correspond. Therefore, the plus and minus of matrices are only applicable when the matrices have equal dimensions.

Adding matrices is very simple. Just add each element in the first matrix to the corresponding element in the second matrix. One of the basic methods that can be done on matrices is the addition process. Just as we plus two or more integers, two or more matrices can also be added similarly. This is identified as the Addition of Matrices.

Multiplying Matrices Concepts

When the number of columns of the 1st matrix should match the number of rows of the 2nd matrix. In other words, To multiply an m × n matrix by an n × p matrix, the ns need to be the equivalent, and the result is an m×p matrix.

(m × n) × (n × p) → m × p

Scalar multiplication is usually multiplying a value through all the parts of a matrix, whereas matrix multiplication is multiplying every part of each row of the first matrix times every element of each column in the second matrix. Scalar multiplication is much more manageable than matrix multiplication; though, a pattern does exist.

When multiplying matrices, the parts of the rows in the 1st matrix are multiplied with corresponding columns in the 2nd matrix. Each note of the resultant matrix is estimated one at a time.

### Introduction to Matrices and Determinants

Now let's understand the concept of matrices and determinants, and their relation.

A determinant seems very much like a matrix, but it is, really, pretty different.

Unlike a matrix, a determinant isn’t simply an array of numbers. It also has a value, which can be determined using methods. The other major difference to take note of now is that even though in a matrix, the number of rows does not have to equal the number of columns. In a determinant, they need to be equal. In short, all determinants are square.

### Concept of Eigenvalues and Eigenvectors

Here’s a short introduction to eigenvalues and eigenvectors with matrix –

For a square matrix B, and Eigenvector and Eigenvalue make equation as :

B ×  x = λ × x

That is just a basic purpose that you can use with eigenvalues and eigenvectors with matrices.

1. Give a Brief Intro to Matrices?

Ans. A matrix algebra can be defined as a concept that consists of an aligned rectangular array of numbers. The numbers in the array have described the elements of the matrix. The horizontal array of factors in the matrix is called rows, and the vertical array of factors are called the columns. If a matrix has m rows and n columns, then it is recognized as the matrix of order m x n.

There are various types of Matrices ;

• Column Matrix

• Row Matrix

• Square Matrix

• Diagonal Matrix

• Scalar Matrix

• Identity Matrix

• Zero Matrix

2. Explain the Concept and Provide an Intro to Matrix Algebra?

Ans. Algebra of Matrices is the part of mathematics, which distributes the vector spaces within different dimensions. The addition of matrix algebra came into continuation because of n-dimensional planes. Algebra of matrices includes the operation of matrices that are Addition, subtraction, multiplication, etc.

Two matrices can be plus/minus, (if and only if) the number of rows and columns of both the matrices are equivalent, or the order of the matrices are similar.

For addition/subtraction, each part of the first matrix is plus/minus to the part present in the 2nd matrix.

The matrix can be Multiplied by 2 methods :

(i) Scalar Multiplication

(ii) Multiplication with another matrix.