# Matrices Mathematics: Matrix

Algorithms

## Matrix System

In mathematics, a matrix is a rectangular array of numbers, symbols, or expressions arranged in rows and columns. Matrices are widely used in various branches of mathematics, physics, computer science, and engineering. Here is a basic overview of the matrix system:

### Matrix Notation:

A matrix is usually denoted by a capital letter. For example, let's use the letter A to represent a matrix.

$A=\left[\begin{array}{cccc}{a}_{11}& {a}_{12}& \cdots & {a}_{1n}\\ {a}_{21}& {a}_{22}& \cdots & {a}_{2n}\\ \mathrm{⋮}\phantom{\rule{0em}{1.5em}}& \mathrm{⋮}\phantom{\rule{0em}{1.5em}}& \ddots & \mathrm{⋮}\phantom{\rule{0em}{1.5em}}\\ {a}_{m1}& {a}_{m2}& \cdots & {a}_{mn}\end{array}\right]$

In this matrix A, the element aij is located in the i-th row and j-th column.

### Matrix Size:

A matrix with m rows and n columns is called an m × n matrix. The size is often written as m × n.

### Special Matrices:

1. Square Matrix: A matrix where the number of rows is equal to the number of columns (i.e., m = n).

$B=\left[\begin{array}{ccc}{b}_{11}& {b}_{12}& {b}_{13}\\ {b}_{21}& {b}_{22}& {b}_{23}\\ {b}_{31}& {b}_{32}& {b}_{33}\end{array}\right]$

2. Identity Matrix (I): A square matrix with ones on the main diagonal and zeros elsewhere.

$I=\left[\begin{array}{ccc}1& 0& 0\\ 0& 1& 0\\ 0& 0& 1\end{array}\right]$

3. Zero Matrix (or Null Matrix): A matrix where all elements are zeros.

$O=\left[\begin{array}{cc}0& 0\\ 0& 0\end{array}\right]$

### Matrix Operations:

1. Matrix Addition: If A and B are matrices of the same size, then their sum A + B is obtained by adding corresponding elements.

2. Scalar Multiplication: If A is a matrix and c is a scalar, then the product cA is obtained by multiplying each element of A by c.

3. Matrix Multiplication: If A is an m × p matrix and B is a p × n matrix, then their product AB is an m × n matrix.

### Transpose of a Matrix:

The transpose of a matrix A is denoted by AT and is obtained by swapping its rows and columns.

${A}^{T}=\left[\begin{array}{cccc}{a}_{11}& {a}_{21}& \cdots & {a}_{m1}\\ {a}_{12}& {a}_{22}& \cdots & {a}_{m2}\\ \mathrm{⋮}\phantom{\rule{0em}{1.5em}}& \mathrm{⋮}\phantom{\rule{0em}{1.5em}}& \ddots & \mathrm{⋮}\phantom{\rule{0em}{1.5em}}\\ {a}_{1n}& {a}_{2n}& \cdots & {a}_{mn}\end{array}\right]$

These are some fundamental concepts of matrices in the mathematical sense. They are extensively used in solving systems of linear equations, transformations, and various other mathematical operations.

#### Programmatic Expression:

Here's an example of a C program that calculates the transpose of a matrix. The program assumes a square matrix, but you can modify it to handle rectangular matrices as needed.

c Copy Code
#include ＜stdio.h>

#define MAX_SIZE 10

void transposeMatrix(int matrix[MAX_SIZE][MAX_SIZE], int rows, int cols, int result[MAX_SIZE][MAX_SIZE]) {
for (int i = 0; i < rows; ++i) {
for (int j = 0; j < cols; ++j) {
result[j][i] = matrix[i][j];
}
}
}

void displayMatrix(int matrix[MAX_SIZE][MAX_SIZE], int rows, int cols) {
for (int i = 0; i < rows; ++i) {
for (int j = 0; j < cols; ++j) {
printf("%d\t", matrix[i][j]);
}
printf("\n");
}
}

int main() {
int matrix[MAX_SIZE][MAX_SIZE], transpose[MAX_SIZE][MAX_SIZE];
int rows, cols;

printf("Enter the number of rows and columns of the matrix: ");
scanf("%d %d", &rows, &cols);

// Input matrix elements
printf("Enter the elements of the matrix:\n");
for (int i = 0; i < rows; ++i) {
for (int j = 0; j < cols; ++j) {
printf("Enter element matrix[%d][%d]: ", i, j);
scanf("%d", &matrix[i][j]);
}
}

// Calculate transpose of the matrix
transposeMatrix(matrix, rows, cols, transpose);

// Display original matrix
printf("\nOriginal Matrix:\n");
displayMatrix(matrix, rows, cols);

// Display transpose matrix
printf("\nTranspose Matrix:\n");
displayMatrix(transpose, cols, rows);

return 0;
}                             

Explanation:

This program first takes the size of the matrix as input, then reads the matrix elements, calculates the transpose, and finally displays both the original and transpose matrices. Adjust the 'MAX_SIZE' macro according to the maximum size of the matrix you want to handle in your program.

Output:
Enter the number of rows and columns of the matrix: 3 3
Enter the elements of the matrix:
Enter element matrix[0][0]: 1
Enter element matrix[0][1]: 2
Enter element matrix[0][2]: 3
Enter element matrix[1][0]: 4
Enter element matrix[1][1]: 5
Enter element matrix[1][2]: 6
Enter element matrix[2][0]: 7
Enter element matrix[2][1]: 8
Enter element matrix[2][2]: 9

Original Matrix:
1       2       3
4       5       6
7       8       9

Transpose Matrix:
1       4       7
2       5       8
3       6       9

This example demonstrates the program with a 3x3 matrix. You can input different matrices by adjusting the size and elements as needed.

#### What's Next?

We've now entered the finance section on this platform, where you can enhance your financial literacy.