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Q&A	Concepts in Advanced Algebra	Q&A

Instruction 1-1

What are Matrices | Adding Matrices | Subtracting Matrices | Determinant | Solving Systems of Equations Using Matrices | Summary

A matrix (plural: matrices) is a rectangular array of numbers. Each of these numbers is called an entry or an element. The elements of a matrix usually are enclosed by two brackets. Here are some examples.
 

 
The horizontal lines of a matrix are called rows and the vertical lines are called columns. The size of a matrix is identified by the number of its rows and columns. The size of a matrix denoted as an index for the label of the matrix. The index usually is in the form of m × n in which m is the number of rows and n is the number of columns.
 
For example, S_{4 × 3} represents a matrix S, which has four rows and three columns. Each element or entry in a matrix is identified by its location. The location of an entry is the point in which the row and the column to which the entry belongs intersect. 

Practice 1. Determine the size of each matrix.

Answer

1. 2 × 4
    
2. 5 × 1
    
3. 1 × 6
    
4. 2 × 6

 
Square Matrix
If a matrix has the same number of rows and columns, it is called a square matrix. Here are some examples.



Practical Exercise 1. Write two arbitrary matrices whose sizes are 2 × 3 and 3 × 2.

Answer

Video Instruction
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• Describing Matrices, Adding and Subtracting, Scalar Multiplication [11:51]