Let's look at:
a1x + b1y = c1
a2x + b2y = c2
solve for x
7.7 Determinant of a Square Matrix
Jan 23­12:40 PM
Let's look at:
a1x + b1y = c1
a2x + b2y = c2
solve for y
Jan 23­12:41 PM
Determinant of a 2 x 2 matrix
A=
a1 b 1
a 2 b2
The determinant is defined as:
det (A) = A = a1b2 - a2b1
Jan 23­12:41 PM
Jan 23­12:43 PM
Find the determinant:
A=
2 -3
1 2
A=
2 -3
1 2
B=
2 1
4 2
a) find det (B)
Jan 23­12:58 PM
Jan 23­12:59 PM
1
A=
2 -3
1 2
Determinant of a 3x3
2 1
B=
4 2
a b c
d e f
g h i
Find AB
a b
d e
g h
Find AB
Jan 23­12:59 PM
Jan 29­12:03 PM
Cramer's Rule
Find the determinant of:
0 2 1
3 -1 2
4 0 1
Jan 29­12:07 PM
Use Cramer's Rule to solve:
4x - 2y = 10
3x - 5y = 11
Jan 29­12:14 PM
x=
c1 b1
c2 b2
a1 b1
a2 b2
y=
a1 c1
a2 c2
a1 b1
a2 b2
Jan 29­12:08 PM
Use Cramer's Rule to solve:
-7x + 11y = -1
3x - 9y = 9
Jan 29­12:15 PM
2
HW: Pg 533 #3-6, 9, 10, 35
& 36 (w/ calc)
Pg 544 # 15-18, 37
Jan 23­1:02 PM
3