ALGEBRA 2
Objective: 1d
Textbooks pages: 199 – 210
Units: 4.5, 4.6
Objective: 1d
 Teacher will ensure students can evaluate
determinants of 2 x 2 and 3 x 3 matrices; find
inverse matrices; use inverse matrices to solve
matrix equations; make real-world connections
with respect to matrices.
 Students will be able too evaluate 2 x 2 and 3 x 3
matrices; find the determinants of each matrices
type; evaluate inverse matrices and make realworld connections using matrices.
Multiplicative Inverse
Will have the following solution:
1
0
0
1
1 0
0 1 0
0 0 1
Matrices are Multiplicative Inverse?
22 11
2.5 1
-2 22
-2
5 -4
-4
(2)(-2) + (1)(5) = 1
(2)(2) + (1)(-4) = 0
(2.5)(-2) + (1)(5) = 0
(2.5)(2) + (1)(-4) = 1
YES
1 0
0 1
Matrices are Multiplicative Inverses?
-3 7
-2 5
-5 7
-2 3
Multiplicative Inverse?
1/5 -1/10
0 1/4
5 2
0 4
Determinant of Matrices
a b
c d
ad - bc
-3 4
2 -5
(-3)(-5) – (4)(2) = 7
Matrix Determinant
6 2
-6 -2
-2 0
2 -1
3 x 3
-3 4 0
2 -5 1
0 2 3
2nd
-1
X
2nd
-1
X
2nd
-1
X
-->
EDIT
3x3
-->
math
#1
#1
enter
values
Your turn
1 -1 2
0 4 2
3 -6 10
22
Inverse + Calculator
-1
-1
2nd
X
-1
MODE
(quit)
#1
-1
X
2 0 -1
-1 -1 1
3 2 0
0.4 0.4 0.2
-0.6 -0.6 0.2
-0.2 0.8 0.4
You try… find Inverse
-2 1 -1
2 04
0 2 5
-4 -3.5 2
-5 -5 3
2 2 -1