-->

# Definition of Matrix

In everyday life a list often contains numbers arranged in columns and rows, such as food items with prices and nutrient levels arranged like the following table,

 Material Nutritional content per kg Price Rupiah per Kg Protein Fat Carbohydrate Milled Rice 68 7 789 2800 Potato 17 0.85 162.35 3000 Know 78 46 16 2000 Milkfish 160 38.4 0 15000 Chicken eggs 115.2 103.5 6.3 7000

Contoh In the table above there is a arrangement of real numbers in the form of a rectangle consisting of 5 rows and 4 columns. This number arrangement is called a 5 x 4 matrix, because each row contains 5 real numbers and each column contains 4 real numbers. The following will be explained about the notation matrix.

### Definition of Matrix: A matrix is ​​a sequence of numbers in a rectangular shape. The numbers in the arrangement are called entries in the matrix.

Example 1

Size (order) matrix is ​​expressed by the number of rows multiplied by the number of columns. In example 1, the matrix size is 3 x 2, 1 x 4, and 1 x 1, respectively.

### Matrix Notation

Our matrix names with uppercase letters, for example: A, B, C, and others. In complete written matrix A = (aij) means that a matrix A consists of entries aij where index i states the i-line and index j declares the j-column of the entry.

A matrix with n rows and n columns is called the square matrix of order n, and entries a11, a22, ..., ann are said to be in the main diagonal of A written:

### Similarity of Matrix

The two matrix are said to be the same if the two matrix have the same size and the corresponding entries in the two matrix are the same.

Example 2
Review the matrix

From these matrix it can be seen that

A(2x2)=B(2x2)= C(2x2), A(2x2)≠D(2x3), B(2x2)≠D(2x3), C(2x2)≠D(2x3)