1. Matrices

2. I Can…
Use matrices to solve problems (3.01)
Use matrices to display and interpret data (3.02)

3. Matrix – a rectangular arrangement of numbers Ex:

4. What is the rule for describing matrices?
= 2 x 3 matrix
= 3 x 1 matrix
= 3 x 2
matrix
= 1 x 1 matrix

5. Dimensions – the number of rows by the number of columns a matrix has.
*Matrices are described by their dimensions
Rows (across) x Columns (up and down)
= 3 x 1 matrix
= 2 x 2 matrix

6. Element – each entry within a matrix
Each element is defined by its position in the matrix.
In a matrix A, an element in row i and column j is represented by aij

7. We name matrices using a capitol letter
Each element will be named using the same letter only lower case

8. Example: A = a11 (read as ‘a one one ’)= 2 (first row, first column) a23 (read as ‘a two three') = 9 (second row, third column) a13 = 5 a21 = a22 = a12 =

9. What is the rule for adding and subtracting matrices?
If: = =
+ = No Solution
What is the rule for adding and subtracting matrices?

10. Adding and Subtracting Matrices
The dimensions must be exactly the same
You add or subtract the corresponding elements

11. Scalar Multiplication
Scalar – a constant (number by itself)
ex: 5, -8, 14
You multiply each element by the scalar
ex: =

12. You try…. = = =

14. Creating Matrices
Data that is organized in columns and rows can be written has a matrix.
Create a matrix for the following information:
Gender
Brown Eyes
Blue Eyes
Green Eyes
Gray Eyes
Male 9 3 1
Female 11 4