Download Holt Algebra 2 4-1

4-1 Matrices
Matricesand
andData
Data
Holt
Algebra
Holt
Algebra
22
4-1 Matrices and Data
Definitions
• Matrix is a rectangular arrangement of
numbers into rows and columns
– Dimensions are read row x column
– Address is read through the location
5/24/2017 1:06 AM
Holt Algebra 2
4.1 Matrix Operations
2
Reading Matrices
A11
1 2 3 A
 4 5 6 A


ROW
13
A21
23
• How many total rows does it have? 2
• How many total columns does it have? 3
• What are its dimensions? 2 x 3
• What is the entry of A22?
Row 2 column 2
• What is the address of 3?
Row 1 column 3
Row X column
5
A13
4-1 Matrices and Data
3x  4 y   8


 2 x  8 y  16
-3
 ____

____
4
A 
2
-8 
____
____


Holt Algebra 2
 ____
-8 
B   16 
 ____ 
4-1 Matrices and Data
Entering a Matrix into the calculator:
• Push 2nd x-1
• Arrow over to edit, use up and down arrows to
select matrix name, enter
• Enter number of rows, 2---enter
• Enter number of columns, 2---enter
• Enter each entry followed by enter.
-3--enter 4---enter 2---enter -8---enter
• 2nd quit to “save” the information in the Matrix
Holt Algebra 2
4-1 Matrices and Data
Entering a Matrix into the calculator:
• Push 2nd x-1
• Arrow over to edit, arrow down to B to select
matrix name, enter
• Enter number of rows, 2---enter
• Enter number of columns, 1---enter
• Enter each entry followed by enter.
-8--enter 16---enter
• 2nd quit to “save” the information in the Matrix
Holt Algebra 2
4-1 Matrices and Data
Using the matrix once it is entered:
•
•
•
•
•
•
2nd x-1
1---enter
x-1 ---enter
2nd x-1
2---enter
enter
Holt Algebra 2
-1
x = 0 and y = -2
4-1 Matrices and Data
The matrix equation representing
Holt Algebra 2
is shown.
4-1 Matrices and Data
To solve the system…
•multiply the inverse of A by B.
A-1B
Holt Algebra 2
x 
 
 y
4-1 Matrices and Data
On the calculator solve the systems
 40 
3 2 
B

A



34 
5  6 
11 
A B 
3.5
1
Holt Algebra 2
1
A B
x  11 and y  3.5
4-1 Matrices and Data
On the calculator solve the systems
 40 
3 2 
B

A



34 
5  6 
11 
A B 
3.5
1
Holt Algebra 2
1
A B
x  11 and y  3.5
4-1 Matrices and Data
Write a system for the following problem
On Monday, Marla babysat for 4 hours, did yard
work for 2 hours, and earned a total of $41. On
Friday, she babysat for 5 hours, did yard work for
3 hours, and earned a total of $55.
What is Marla’s hourly rate for each activity?
A. Write a system of equations.
Let x=Marla’s hourly rate for babysitting
and y=her hourly rate for yard work
B. Write a Matrix for the system
Holt Algebra 2
4-1 Matrices and Data
4 x  2 y  41

5 x  3 y  55
1
A B
4
A
5
 41
2
B




3
55
6.5
 
7.5
Marla gets paid $6.50/hour for babysitting
and $7.50/hour for yard work.
Holt Algebra 2