Bell RingerBell Ringer
Find the Find the averageaverage of each set of numbers. of each set of numbers. - add up and divide by # of items- add up and divide by # of items
4.4. 12, 15, 7, 21, 18, 19, 2012, 15, 7, 21, 18, 19, 20
6.6. 25, 29, 33, 28, 28, 2725, 29, 33, 28, 28, 27
8.8. 89, 95, 86, 81, 97, 82, 80, 81, 93, 95, 97, 8089, 95, 86, 81, 97, 82, 80, 81, 93, 95, 97, 80
What is a Matrix?What is a Matrix?
A A matrixmatrix is a rectangular array of data is a rectangular array of data entries (elements) displayed in entries (elements) displayed in rowsrows and and columnscolumns and enclosed in brackets. and enclosed in brackets.
The number of rows and columns in the The number of rows and columns in the matrix determines its dimensionsmatrix determines its dimensions..
Defined as:Defined as:Row X ColumnRow X Column
RowsRows go across go across ColumnsColumns go up and down go up and down
Example:Example:
[ ]2 4
6 9
5 3
This is a 3 x 2 matrixThis is a 3 x 2 matrix
Because you haveBecause you have
3 rows and 2 columns3 rows and 2 columns
You try!You try!Name These Matrices!Name These Matrices!
[ ]4 5 6
2 3 4 [ [] ]1 -4 12 6
12 –3 8 4
3 4 8 8
1 4
4 6
ADDING MATRICESADDING MATRICES
To add 2 or more matrices , must have the same frame.
“same number of rows and columns”
If you don’t, then they can not be added.
DefinitionsDefinitions
““corresponding entries”corresponding entries” --add the two numbers that are in the add the two numbers that are in the
exact same positionexact same position in each matrix. in each matrix.
YOU TRYYOU TRY
[][[
]]3 7 53 7 5
22 4 64 6
1 1 11 1 1
+5 6 25 6 2
22 4 14 1
1 3 61 3 6
= =[ ]
__ by ____ by __
matrixmatrix
SUBTRACTIONSUBTRACTIONThe same rules as addition apply.The same rules as addition apply.
[][[
]]5 85 8
3 63 6-
11 55
1 41 4
= = [ ]
SUBTRACTIONSUBTRACTIONThe same rules apply as for additionThe same rules apply as for addition
[][[
]]8 48 4
7 97 9-
-2 3-2 3
5 -115 -11
= = [ ]
YOU TRYYOU TRY
[][[
]] -
= =[ ]
__ by ____ by __
matrixmatrix
5 -7 95 -7 9
2 4 -62 4 -6
8 -7 58 -7 5
2 -3 52 -3 5
6 -3 76 -3 7
-5 9 1-5 9 1