Reflections

1. 9.3 Reflections
February 13, 2014
Bellwork
Add or subtract
[6.3 –3.1]
1. [2.8 –9.2] + [3.5 6.1]
3. Triangle ABC has vertices A(2, –1 ), B(1, 3), and C
(–2, –2). Write a matrix equation that shows how to
find the image matrix that represents the
translation of ABC 4 units left and 5 units up.
Jan 27­9:14 AM
HW pg. 593 #4­22 even
1

2. 9.3 Reflections
February 13, 2014
9.3 Reflections
snoitcelfeR 3.9
Line of reflection: mirror line
Jan 27­10:41 AM
HW pg. 593 #4­22 even
2

3. 9.3 Reflections
February 13, 2014
Jan 27­11:49 AM
HW pg. 593 #4­22 even
3

4. 9.3 Reflections
February 13, 2014
Coordinate Rules for Reflections
x-axis: (x,-y)
y-axis: (-x,y)
y = x: (y, x)
y = -x: (-y,-x)
snoitcelfeR
Jan 27­12:31 PM
HW pg. 593 #4­22 even
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5. 9.3 Reflections
February 13, 2014
Reflection Theorem: A reflection is an isometry.
Jan 27­11:46 AM
HW pg. 593 #4­22 even
5

6. 9.3 Reflections
February 13, 2014
Reflection Matrix
To find the reflected image, write the reflection matrix to the left
of the pre-image matrix, then multiply.
[ ]
x-axis: 1 0
0 -1
[
y-axis: -1
0
]
0
1
Jan 27­1:34 PM
HW pg. 593 #4­22 even
6

7. 9.3 Reflections
February 13, 2014
HW pg. 593 #4-22 evens
Jan 27­1:33 PM
HW pg. 593 #4­22 even
7