404 Transformation geometry (Chapter 20)
EXERCISE 20A
1 Find the image point when:
a (2,¡1) is translated through
¡ 3
4
¢
b (5,2) is translated through
¡¡ 1
4
¢
:
2 If (3,¡2) is translated to (3,1), what is the translation vector?
3 What point has image (¡ 3 ,2) under the translation
¡¡ 3
1
¢
?
4 Find the translation vector which maps:
a A onto E b E onto A
c A onto C d C onto A
e B onto E f D onto E
g E onto C h E onto D
i D onto B j A onto D.
When we
translate point A,
we often label its
image A^0.
5 Triangle ABC has vertices A(¡ 1 ,3),B(4,1) and C(0,¡2):
a Draw triangle ABC on a set of axes.
b Translate the figure by the translation vector
¡ 4
¡ 2
¢
.
c State the coordinates of the image vertices A^0 ,B^0 and C^0.
d Through what distance has each point moved?
6 What single transformation is equivalent to a translation of
¡ 2
1
¢
followed by a
translation of
¡ 3
4
¢
?
7 Find the equation of the image line when:
a y=2x+3is translated
¡¡ 1
2
¢
b y=^13 x+2is translated
¡ 3
0
¢
c y=¡x+2is translated
¡ 2
3
¢
d y=¡^12 x is translated
¡¡ 2
¡ 5
¢
:
When P(x,y) moves under arotationabout O through an
angle ofμto a new position P^0 (x^0 ,y^0 ), then OP=OP^0 and
POPb^0 =μwherepositiveμis measuredanticlockwise.
O is the only point which does not move under the rotation.
We will concentrate on rotations of 90 o(both clockwise and
anticlockwise) and 180 o.
B ROTATIONS [5.4, 5.6]
A
B
E
C
D
y
x
q P(!'\\@)
P' ' '(! '\\@ )
O
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y:\HAESE\IGCSE01\IG01_20\404IGCSE01_20.CDR Friday, 3 October 2008 3:38:47 PM PETER