8.40 ୋ 8
ˀ࢛ reflection ˀ࢛ൿ axis of reflection
(a) Al ٙѬᅺ = (5 , -1 + 4) = (,)53
Bl ٙѬᅺ = (5 , -4 + 4) = (,)50
Cl ٙѬᅺ = (2 , -1 + 4) = (,)23
(b)
A
B
C
1
1
0 2 3 4 5 6
-1
-2
-3
-4
2
3
4 y
x
A'
B'
C'
解
B 反射
ίྡʕ�ҢࡁҪ P ᓃضٜᇞ l ᔕᔷЇ̤ɓᗙ�Ց Pl ᓃ�
m
P
m
m
P P'
வ၇ᜊ౬၈މᓃٙˀ࢛�Ͼٜᇞ l ၈މˀ࢛ൿ�
�ضٜᇞ l�͵̙ᄳЪ�࿁ٜᇞ l��
◀
ྡʕהͪމ 3PQR�Չᓃ݊ P(-3 , 4)�Q(-1 , 1) ʿ R(-2 , 1)�
P�Q ʿ R ʱйΣ̛̻ 3 ఊЗЇ Pl�Qlʿ Rl�
QR
P
1
1
0 2 3
-3 -2 -1
2
3
4 y
x
(a) Ӌ Pl�Ql ʿ Rl ٙѬᅺ�
(b) ίྡʕᖭ 3PlQlRl�
14
即時訓練即時訓練
➥ ୦ᕚ 8D 13
Pl(0 , 4)�Ql(2 , 1)�Rl(1 , 1)
Q'R'
P'