http://www.ck12.org Chapter 8. Systems and Matrices
8.3 Matrices to Represent Data
Here you will learn what a matrix is and how to use one to represent data.
A matrix is a rectangular array of numbers representing data in a variety of forms. Computers work very heavily
with matrices because operations with matrices are efficient with memory. Matrices can represent statistical data
with numbers, but also graphical data with pictures.
How might you use a matrix to write the following image as something a computer could recognize and work with?
MEDIA
Click image to the left for use the URL below.
URL: http://www.ck12.org/flx/render/embeddedobject/61418http://www.youtube.com/watch?v=ilFJYjfKYjk James Sousa: Dimensions of a Matrix
Guidance
A matrix is a means of storing information effectively and efficiently. The rows and columns each mean something
very specific and the location of a number is just as important as its value. The following are all examples of
matrices:
[1 2 3
4 5 6]
,
1 0 0
0 1 0
0 0 1
,
2 3 4 5
0 4 5 0
0 0 2 − 9
0 0 0 10
The entries in a matrix can be written out using brackets like [ ], but they can also be described individually using
a set of 2 subscript indicesiandjthat stand for the row number and the column number. Alternatively, the matrix
can be named with just a capital letter likeA.
A= [ai j] =
[a
11 a 12
a 21 a 22