Functions
Functions
The exemplar questions provided in this document will be continuously upgraded every
year with new questions that align with the latest trends in final Maths exams.
Teachers may use or adapt any of these questions in their own tests and exams.
This document is available in WORD format which will allow teachers to copy and paste
selected questions. To receive the questions in WORD format, please send an email to
Mark Phillips (mathmark@mweb.co.za).
C Financial mathematics
E Differential calculus
F Probability
All questions are adapted from past matric preliminary and final examinations or are
original.
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2
QUESTION 1 Grade 11
1.1.1 Draw a neat sketch graph indicating the coordinates of the intercepts with
the axes, the coordinates of the turning point and the equation of the axis
of symmetry. (6)
1.2.6 If the graph of g is shifted 3 units left and 1 unit upwards, state the
equation of the newly formed graph. (2)
QUESTION 2 Grade 11
f ( x) 2x1 1 g ( x) x 1
2
2.2 Given: f ( x)
x
2.2.1 Sketch the graph of y f ( x 2) 1 . (4)
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3
QUESTION 3 Grade 11
x 1
2 1
Given: f ( x) x 2 4 x g ( x) 1 h( x ) 2 2
x2 2
3.1 Sketch the graph of f showing intercepts with the axes, the turning point
and the axis of symmetry. (6)
3.2 Sketch the graph of g showing intercepts with the axes and the asymptotes. (6)
3.3 Sketch the graph of h showing the intercepts with the axes and the horizontal
asymptote. (4)
QUESTION 4 Grade 11
f ( x) 3x1 1 and g ( x) 2 x 2
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4
QUESTION 5 Grade 11
x 1
1
Given: f ( x) 4( x 1) 3 and g ( x)
2
2
3
5.1 Write down the coordinates of the turning point of the graph of f. (2)
5.2 Write down the equation of the asymptote of the graph of g. (1)
5.3 Show that the graph of g passes through the turning point of f. (2)
5.4 Explain why the graph of f will never cut the x-axis. (2)
5.7 Sketch the graphs of f and g on the same set of axes. (7)
QUESTION 6 Grade 12
QUESTION 7 Grade 12
Given: f ( x) 3x
7.2 Sketch the graph of f and f 1 on the same set of axes. (3)
7.3.2 x. f 1 ( x) 0 (1)
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5
x 1
1
8.1 Given: g ( x) 2 2
2
1
8.2.3 State the equation of f in the form g ( x) ... (1)
9.1.1 Determine the coordinates of the intercepts of f with the axes. (3)
9.1.2 Sketch the graph of f showing the intercepts with the axes and the horizontal
asymptote. (3)
9.1.3 Write down the equation of g if g is the graph of f shifted 3 units right and
2 units up. (2)
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6
QUESTION 10 Grade 11
4
In the diagram below, the graphs of f ( x) 2 and g ( x ) a ( x p ) 2 q are shown.
x 1
The graph of f and g both cut the y-axis at B and the graph of f has its turning point at A, the
point of intersection of the asymptotes of f . The graph of f cuts the x-axis at C.
The line h is an axis of symmetry of f which intersects the graph of f at the point ( 1 ; 4) and
passes through A.
(1; 4)
10.3 Determine the equation of h and hence the equation of the other axis of
symmetry of h. (4)
10.5.1 f ( x ) 0 (3)
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7
(3; 2)
y x 3
x 1
11.9 If f represents h , the graph of the derivative of a function h, for which value
of x will h have a minimum turning point? (1)
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8
QUESTION 12 Grade 11
A(1 ; 2)
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(2 ; 8)
f yx
6
g
y 1
x 1
1
13.1 Show that a , b 2 and c 6 by determining the equation of f. (3)
2
13.2 Determine the length of AB. (4)
13.5.1 g ( x) x 0 (2)
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C(2 ; 4)
1
14.1 Show that a . (2)
2
14.2 Determine the length of AB. (3)
14.7.1 g 1 ( x) 2 (3)
14.7.2 x . f ( x) 0 (2)
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11
QUESTION 15 Grade 11
4
The diagram below shows the hyperbola defined by f ( x) 1
x p
The lines g and y x 2 are axes of symmetry of f and intersect at B, the point of
intersection
of the asymptotes.
y x 2
15.4 Suppose that the graph of f is shifted left so that A coincides with the origin.
Determine the equation of the vertical asymptote of the newly formed graph. (3)
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12
QUESTION 16 Grade 11
a
In the diagram below, the graph of f ( x) q cuts the y-axis at 3 and the x-axis at
x p
A. The graph of g ( x ) m( x n) 2 c intersects f at A, cuts the y-axis at 3 and has a
B(2;1)
y 2
3
x2
Determine:
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13
QUESTION 17 Grade 11
a
In the diagram below, the graphs of f ( x) dx2 and g ( x) q intersect at P( 2 ; 2)
x p
and Q. The asymptotes of g intersect at A( 1;1) .
P(2 ; 2)
A(1;1)
17.3.2 the values of k for which f ( x) k 0 has real, unequal roots. (1)
1
17.3.3 the values of k for which 1 0 has a negative root. (1)
xk
17.6 If the graph of f is shifted 2 units left and 4 units down, determine the
x-intercepts of the newly-formed graph. (4)
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14
QUESTION 18 Grade 11
18.3 Determine the values of k for which f ( x) k 0 has two negative, unequal
roots. (2)
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15
QUESTION 19 Grade 11
(2 ; 5)
(1; 2)
Determine:
19.1 the value of k, p and r. (5)
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16
QUESTION 20 Grade 11
In the diagram below, the graphs of the following functions are shown:
x
3 and g ( x) 2
6 1
f ( x)
x 1 2
The graph of f cuts the x-axis at A and the y-axis at B. The graphs of f and g intersect at E.
C and D are points on the graphs of f and g respectively such that line segment CD
produced to H, a point on the x-axis, is parallel to the y-axis.
Determine:
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17
QUESTION 21 Grade 11
The graphs of the following functions are drawn in the diagram below:
f ( x) ax2 bx c , g ( x ) 4 and h( x) x 5
( p ; q)
21.4 Hence, write down the length of JK, if JK is parallel to the y-axis. (2)
21.5 Use the graph to determine for which value(s) of k will x2 6 x k 0 have
real and unequal roots? (2)
f ( x)
21.6 For which values of x is 0? (3)
h( x )
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QUESTION 22 Grade 11
C(4 ;10)
22.7 Determine the coordinates of the turning point of the graph y f ( x 2) 1 . (2)
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19
P(3 ; 2)
16
23.5 If f represents the graph of the gradient of a cubic function h, determine the
values of x for which the graph of h is concave up. (3)
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20
8
Sketched below are the graphs of f ( x) , x 0 and g ( x ) a x .
x
P is the reflection of the point Q(4 ; 2) in the line y x .
yx
Q(4 ; 2)
QUESTION 25 Grade 11
a
The axes of symmetry of the graph of the hyperbola y q are y x and
x p
y x 2 .
25.1 Determine the coordinates of the point of intersection of the two axes
of symmetry. (3)
25.3 If the hyperbola is shifted 3 units left and 4 units up, write down the equation
of the newly formed graph. (2)
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21
A(4 ; 5)
F(1; 0)
26.6 Determine the maximum length of BG if it varies in length between A and D. (4)
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22
QUESTION 27 Grade 11
Given: f ( x) 6 3 and g ( x) 6 q
x2 x p
27.1 Write down the equations of the asymptotes of f . (2)
27.6 Describe how the graph of f is translated to form the graph of g. (2)
QUESTION 28 Grade 12
y f 1 ( x)
(16 ; 2) y g 1 ( x)
(4 ;1)
28.1 Write down the coordinates of ONE point through which both the graphs of
f and g pass. (1)
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23
QUESTION 29 Grade 11
f ( x) x 2 3 x 4 g ( x) 2 x 8 h( x) ab x q
The graph of f cuts the x-axis at A and C and the y-axis at D and has a turning point at E.
The graph of f and g intersect at B and C. The graph of h cuts the x-axis at A and the y-axis
at F and its asymptote passes through D. F is the point (0 ; 1) .
F(0 ;1)
29.3 Determine the value of x for which the graph of f has a minimum value. (2)
29.5 For which value of k will x2 3x 4 2 x k have two real roots that are
opposite in sign? (2)
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0 ( x 2) 2 1
( x 2)2 1 (0 ; 3)
x 4x 4 1
2
x2
x2 4 x 3 0
( x 1)( x 3) 0
x 1 or x 3
(1; 0) and (3 ; 0)
Axis of symmetry: x 2
Turning point: (2 ; 1)
1.1.2 Range: y ( ; 1] answer (1)
1.2.1 f ( x) x 2 2 x 3 xTP 1
(2) yTP 4 (3)
xTP 1
2(1)
yTP (1) 2 2(1) 3 4
(1; 4)
1.2.2 0 x2 2 x 3 0 x2 2 x 3
0 ( x 3)( x 1) 0 ( x 3)( x 1)
x 3 or x 1 x 3 or x 1 (3)
1.2.3 shape
x 1 turning point
intercepts with axes (3)
(1; 0) (3 ; 0)
(0 ; 3)
(1; 4)
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25
QUESTION 2
(0 ;1)
(1; 0)
y 1
(0 ;1)
(1; 0) (1; 0)
y 1
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26
QUESTION 3
3.1 x-intercepts
y-intercept
axis of symmetry
turning point (6)
(0 ;0) (4 ; 0)
(2 ; 4)
3.2 x 1
y 2
y-intercept
x-intercept
shape (6)
(2 ;1)
2 12
y 2
(2 ; 3)
(0 ; 5)
x 1
3.3 y 2
x 1
1 y-intercept
y 2 2
2 x-intercept
shape (4)
(0 ; 2)
(1; 0)
y 2
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27
QUESTION 4
4.1 y 1 y 1 (1)
4.2 y2 01
1 Let x 0
(0 ; 1) (2)
y 1
(0 ;1)
4.3 0 2 x 1 1 Let y 0
1 2 x 1 0 2x1 1
( 1 ; 0) (3)
20 2 x 1
0 x 1
x 1
( 1; 0)
4.4 intercepts with axes
y 3x 1 1 asymptote
shape (3)
(0 ; 2)
(1; 0) (1; 0)
y 1
y 2 x 2
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28
QUESTION 5
5.1 (1 ; 3) 1
3 (2)
5.2 y2 y2 (1)
5.3 Substitute x 1 in the equation of g: substituting x 1
11 y3
1
y 23 stating that g passes
3
through f. (3)
The graph of g passes through the point (1 ; 3) which is
the turning point of f.
5.4 The graph of f has a minimum value of 3. stating minimum value (2)
5.5 y 4(0 1)2 3 7 x0
7 (2)
5.6 01 x0
1
y 25 5 (2)
3
5.7 For the graph of f:
x 1 shape
f turning point
y-intercept
For the graph of g:
(2 ;7) shape
asymptote
5 y-intercept
(1; 3) g intersecting point (7)
y2
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29
QUESTION 6
6.1 shape
one point indicated (2)
(1; 2)
6.2 y 2 x2 x 0 f x 2 y2
x 2 y2 y 0 f 1 y x (2)
2
x y2
2
y x (x 0)
2
6.3 shape
one point indicated (2)
yx
(1; 2)
(2 ;1) f 1
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30
QUESTION 7
f 1
(0 ;1) (3 ;1)
(1; 0)
(0 ; 23 )
(1; 0)
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31
QUESTION 8
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32
QUESTION 9
9.1.1 y-intercept: (0 ; 1)
y 40 2 40 2 1 0 4 x 2
(0 ; 1) 1
; 0 (3)
x-intercept: 2
0 4 x 2
2 (22 ) x
21 22 x
1 2 x
2 x 1
1
x
2
1
; 0
2
9.1.2 y 2
intercepts shown
shape (3)
( 12 ; 0)
(0 ; 1)
y 2
(0 ; 3)
(1; 0)
y 1
(1; 2)
(4 ; 4)
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33
9.2.2 y 4x ; x 0 f x 4y
x 4y ; y 0 f 1 y x2
1
4
x2 4 y
1
1 2 h( x ) x 2
y x ; x0 4
4 x0 (4)
1
y x2 h
4
1
h( x ) x 2 ; x 0
4
9.2.3 See diagram in 6.1 shape
x-intercept
y-intercept
asymptote (4)
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34
QUESTION 10
10.1 The vertical asymptote x 1 intersects with the stating the asymptotes
horizontal asymptote y 2 at the point (1 ; 2) . point of intersection
A is the point (1; 2) of asymptotes (2)
10.2 y a( x 1)2 2 y a( x 1)2 2
y-intercept of f : y6
4 6 a (0 1) 2 2
y 2
0 1 a4
y 6 g ( x) 4( x 1)2 2
B(0 ; 6) (5)
Substitute B:
6 a(0 1) 2 2
a 4
g ( x) 4( x 1) 2 2
10.3 y ( x p ) q y ( x 1) 2
y ( x 1) 2 h( x ) x 3
y x 1 2 y x 1 2
h( x ) x 3 y x 1 (4)
y ( x p) q
y x 1 2
y x 1
10.4 y [2 ; ) y [2 ; ) (1)
10.5.1 x-intercept of f : 4
4
0 2
0 2 x 1
x 1 x3
0 4 2( x 1) 1 x 3 (3)
0 4 2 x 2
0 2x 6
2 x 6
x 3
C(3 ; 0)
f ( x) 0 for all 1 x 3
10.5.2 f ( x).g ( x) 0 for all x 1
x 1 or x 3 x3 (2)
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35
QUESTION 11
Alternatively:
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36
Alternatively:
0 ( x 1) 2 4
4 ( x 1) 2
2 x 1
2 x 1 or 2 x 1
x 3 or x 1
CD 4 units
11.7 h( x) [( x 1) 2 4] 2 ( x 1) 2 4 2 h( x) ( x 1)2 6
h( x) ( x 1) 2 6 6 (2)
max value is 6
11.8 x-intercept of g: 4
0 4
4 x 1
0 4 x2
x 1
0 4 4( x 1) x2 (3)
0 4 4x 4
4x 8
x 2
f ( x).g ( x) 0 for
x2
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37
QUESTION 12
12.1 y ax substitution
Substitute (1; 2) : f ( x) 2 x (2)
2 a1
a 2
f ( x) 2 x
12.2 y a ( x 3) 2 6 y a ( x 3) 2 6
Substitute: (1; 2): substitution
2 a (1 3) 2 6 a 1
equation (4)
4 4a
a 1
g ( x ) ( x 3) 2 6
12.3 0 ( x 3) 2 6 0 ( x 3) 2 6
( x 3) 2 6 x 3 6
x 3 6 (3 6) (3 6)
x 3 6 2 6 (4)
EF xF xE
EF (3 6) (3 6) 2 6
12.4 h( x) f ( x 1) 1 2 x1 1
2 x 1 1 y (1; ) (3)
Range: y (1; )
12.5 f ( x).g ( x ) 0 for all: answer (1)
3 6 x 3 6
12.6 Graphically: k 9 (2)
k 9
Algebraically:
(6) 2 4( 1)( k ) 0
k 9
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38
QUESTION 13
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39
13.6 1 1
x2 2 x k 6 x2 2 x 6 k
2 2
1 k 8 (2)
x 2 2 x 6 k
2
This is where the parabola cuts the line
y 8 in one point only (two equal solutions)
k 8
Alternatively:
1 16 2k
x2 2 x 6 k 0 k 8
2
1
(2) 2 4 (6 k )
2
4 2(6 k )
4 12 2k
16 2k
For equal roots, 0
0 16 2k
k 8
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40
QUESTION 14
14.1 y ax substitution
answer (2)
4 a 2
1
4
a2
4a 2 1
1
a2
4
1
a
2
14.2 0 2 x2 4 x 6 equating to 0
x-values
0 x2 2 x 3 length of AB (3)
0 ( x 3)( x 1)
x 3 or x 1
AB 4 units
14.3 4 x-value of R
xR 1 y-value of R
2(2)
length of SR (5)
yR 2(1)2 4(1) 6 8
SR 8 units
Alternatively:
f ( x) 4 x 4
0 4x 4
x 1
14.4 h( x) 2( x 1) 2 8 answer (1)
14.5 x interchanging x and y
1
y equation (2)
2
y
1
x
2
y log 1 x
2
14.6 shape
x-intercept (2)
The other point is optional.
(1 ; 0)
(2 ; 1)
y log 1 x
2
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41
14.7.1 equation
x-value
y log 1 x 0 x4 (3)
2
y 2
(4 ; 2)
log 1 x 2
2
2
1
x 4
2
g 1 ( x) 2 for all 0 x 4
14.7.2 1 x 0 answer (2)
QUESTION 15
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42
QUESTION 16
16.1 a a
y 2 y 2
x2 x2
Substitute (0 ; 3) : a2
2
3
a
2 f ( x) 2 (4)
02 x2
a
1
2
a 2
2
f ( x) 2
x2
16.2 y m( x 2)2 1 y m( x 2)2 1
Substitute (0 ; 3): m 1
3 m(0 2) 2 1 g ( x) ( x 2) 2 1 (4)
4 m(2) 2
4 4m
m 1
g ( x) ( x 2) 2 1
16.3 2 equating to 0
0 2 x3
x2
0 2 2( x 2) OA 3 units (3)
0 2 2x 4
2x 6
x 3
OA 3 units
Alternatively:
0 ( x 2) 2 1
( x 2) 2 1
x2 4 x 4 1
x2 4 x 3 0
( x 1)( x 3) 0
x 1 or x 3
OA 3 units
16.4 f ( x).g ( x ) 0 for all 1 x 2
1 x 2 or x 3 x 3
(3)
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43
QUESTION 17
17.1 a a
y 1 y 1
x 1 x 1
Substitute the point ( 2 ; 2) : a 1
p 1
a
2 1 q 1
2 1
1
a d (6)
1 2
1
a 1
1
y 1
x 1
p 1, q 1, a 1
y dx 2
Substitute the point ( 2 ; 2) :
2 d ( 2) 2
1
d
2
1 2
y x
2
17.2 1 substituting x 1
Substitute x 1 into the equation y 1 :
x 1 y 12
1 1 Q(1; 12 )
y 1 . (4)
11 2
OR
1 2
Substitute x 1 into the equation y x :
2
1 2 1
y (1)
2 2
Therefore, Q is the point Q(1; 12 ) .
Alternatively:
equating
1 1
1 x2 solving equation
x 1 2
y 12
2 2 x 2 x3 x 2
Q(1; 12 )
0 x x 2x
3 2
0 x( x 2 x 2)
0 x( x 2)( x 1)
x 0 or x 2 or x 1
Substitute x 1 into either of the two equations:
1 2 1
y (1)
2 2
Q is the point (1; 12 ).
17.3.1 f ( x).g ( x) 0 for 1 x 0. 1 x 0 (2)
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44
17.3.2 k 0 k 0 (1)
17.3.3 k 1 k 1 (1)
17.4 1 2 1 1 2 1
BC x 1 x 1
2 x 1 2 x 1
1 1 substituting x 4
x2 1 1
2 x 1 7 (3)
Substitute x 4 : 5
1 1 1
BC (4) 2 1 7
2 4 1 5
17.5 1 1
h( x ) 1 2 3
( x 3) 1 x2
1 asymptotes (3)
3
x2
Vertical asymptote: x2
Horizontal asymptote: y 3
17.6 1 1
y ( x 2) 2 4 y ( x 2) 2 4
2 2
1 x 2 8
0 ( x 2) 2 4
2 x 0,83
( x 2) 2 8 x 4,83 (4)
x 2 8
x 2 8
x 0,83 or x 4,83
Alternatively:
1 1
y ( x 2) 2 4 y ( x 2) 2 4
2 2
1 using quadratic formula
0 ( x 2) 2 4 x 0,83
2
x 4,83
( x 2) 2 8
x2 4 x 4 8
x2 4 x 4 0
4 (4) 2 4(1)(4)
x
2(1)
4 32
x
2
x 2 2 2
x 0,83 or x 4,83
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45
QUESTION 18
18.1.1 D( 4 ; 0) D( 4 ; 0) (1)
18.1.2 D( 4 ; 0) , C(1 ; 0) and A(0 ; 4) . y a ( x 4)( x 1)
y a ( x 4)( x 1) a 1
4 a (0 4)(0 1) y x2 3x 4
a 1 a 1, b 3 and c 4 (4)
y 1( x 4)( x 1)
y x 2 3x 4
a 1, b 3 and c 4
18.1.3 x 2 3x 4 x 4 x 2 3x 4 x 4
x2 2 x 8 0 x2 2 x 8 0
( x 4)( x 2) 0
( x 4)( x 2) 0
x 4 or x 2
x 4 or x 2 R(4 ; 8) (5)
y 44 8
R(4 ; 8)
18.1.4 NP ( x 4) ( x 2 3 x 4) NP ( x 4) ( x2 3x 4)
NP x 4 x 2 3 x 4 NP x2 2 x 8
2
NP x 2 2 x 8 3 3
NP 2 8
3 2 2
At x 1 12 3
2 NP 8 (4)
2 4
3 3
NP 2 8
2 2
9
NP 3 8
4
3
NP 8
4
18.2 f ( x) . g ( x) 0 for all x 1. x 1. (1)
18.3 3
2
3 1 4k
yP 3 4 6 1
2 2 4 k 6 (2)
4
1
f ( x) k 0 for all 4 k 6
4
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46
QUESTION 19
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47
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48
QUESTION 20
20.1 x 1 x 1
y3 y3 (2)
20.2 y ( x 1) 3 y ( x 1) 3 y x4
y x4 y x 4 y ( x 1) 3
y x 4 (3)
20.3 x ( ; ) answer (1)
20.4 6 6
0 3 0 3
x 1 x 1
0 6 3( x 1) x 1
0 6 3 x 3 OA 1 unit
6
3 x 3 y 3 3
0 1
x 1 OB 3 units
OA 1 unit (5)
6
y 3 3
0 1
OB 3 units
CD f ( x) g ( x)
1
20.5 x
6
CD 3 2 x 2
x 1 2 92
At x 2 7 units (5)
2
6 1
CD 3 2
2 1 2
9 2
7 units
20.6 6 f (3) 6
f (3) 3 6
3 1 g (3) 6
3 E(3 ; 6) (3)
1
g (3) 26
2
E(3 ; 6)
20.7 x 1 x 1 (2)
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49
QUESTION 21
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50
QUESTION 22
22.1 2 x2 4 x 6 0 Let y 0
x-intercepts
x2 2 x 3 0
AB 4 units
( x 3)( x 1) 0 (3)
x 3 or x 1
AB 4 units
22.2 4 x 1
x 1 y 8
2(2)
FG 8 units
y 2(1) 2 4(1) 6 8 (3)
G( 1; 8)
FG 8 units
22.3 B(1; 0) and C( 4 ;10) mBC 2
10 0 g ( x) 2 x 2
mBC 2
4 1 a 2 and b 2 (3)
y 2 x c
0 2(1) c
c2
g ( x) 2 x 2
a 2 and b 2
22.4 DE (2 x 2) (2 x 2 4 x 6) 2 x2 6 x 8
2 x 2 6 x 8 2 x2 6 x 4 0
x 2 or x 1
12 2 x 2 6 x 8
OH 2 units (4)
2x 6x 4 0
2
x 2 3x 2 0
( x 2)( x 1) 0
x 2 or x 1
OH 2 units
22.5 f ( x).g ( x ) 0 for all x 3 or x 1 x 3
x 1
(2)
22.6 k 2 k 2 (1)
22.7 (1 2 ; 8 1) 1
(1; 7) 7 (2)
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51
QUESTION 23
23.1 y a ( x 3) 2 2 y a ( x 3) 2 2
Substitute (0 ; 16) : value of a
16 a (0 3) 2 2 y 2( x 3)2 2
18 9a y 2 x 2 12 x 16 (4)
a 2
y 2( x 3)2 2
2( x 2 6 x 9) 2
2 x 2 12 x 16
23.2 x 2 2 x 2 12 x 16 equating
standard form
2 x 2 11x 14 0 factors
(2 x 7)( x 2) 0 x-values
7 y-values (5)
x or x 2
2
7 3
y 2
2 2
7 3
D ;
2 2
23.3 x4 answer (1)
23.4 2 units down. 2 units down
3 units left. 3 units left (2)
23.5 f ( x) 2 x 2 12 x 16 f ( x) 4 x 12
f ( x) 4 x 12 4x 12 0
x3 (3)
4 x 12 0
4 x 12
x 3
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52
QUESTION 24
24.1 P(2 ; 4) 2
4 (2)
24.2 A(0 ; 1) A(0 ; 1) (1)
24.3 4 a 2 substitution
value of a (2)
1
4 2
a
1
a2
4
1
a
2
24.4
1
x
1
y g y
2 2
y y log 1 x
1
g 1
2
x (2)
2
y log 1 x
2
24.5 x 2 x 2 (1)
24.6 8 8
k ( x) k ( x)
x2 x2
x 2 x2 (2)
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53
QUESTION 25
25.1 x x 2 x x 2
2 x 2 x 1
( 1 ; 1) (3)
x 1
y 1
The axes of symmetry intersect at ( 1 ; 1) .
25.2 The asymptotes also intersect at the point of a
intersection of the axes of symmetry. y 1
x 1
a2
Vertical asymptote: x 1
x 1 0 p 1
Horizontal asymptote: y 1 q 1 (4)
a
y 1
x 1
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54
QUESTION 26
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55
26.5 h( x ) f ( x ) 1 (2 x) 2 8
( x 2) 2 9 1 (2 ; 8)
(3)
(2 x) 2 8
Axis of symmetry of h is:
2 x 0
x 2
The turning point of h is (2 ; 8) .
Alternative: reflection in y-axis and
The graph of h is the reflection of f in the y-axis and a shift of 1 down.
shift of 1 unit down. (2 ; 8)
The turning point of f is (2 ; 9) . (3)
Therefore, the turning point of h is (2 ; 8) .
26.6 BG ( x2 4x 5) (2 x 3) x2 2 x 8
There are three methods of finding the maximum
length.
Method 1 Completing the square x2 2 x 8
BG x 2 2 x 8 completing the square
9 (4)
( x 2 2 x ) 8
( x 2 2 x 1 1) 8
[( x 1) 2 1] 8
( x 1) 2 9
Maximum length of BG is 9.
x2 2 x 8
Method 2 The formula substitution in formula
x 1
(2)
x 1 substitution to get 9 (4)
2(1)
Maximum BG (1)2 2(1) 8 9
x2 2 x 8
Method 3 Calculus 2x 2 0
d (BG) 2 x 2 0 x 1
dx substitution to get 9 (4)
x 1
Maximum BG (1) 2 2(1) 8 9
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56
26.7.1 y 2 x 3 g g 1 ( x) 1 x 3 (1)
1 2 2
x 2 y 3 g
2 y x 3
y 1 x 3
2 2
g 1 ( x) 1 x 3
2 2
26.7.2 sketching two graphs
2 x 3 1 x 3
2 2 x 1
4 x 6 x 3 x 1 (3)
3x 3
x 1
y g ( x) 2 x 3
1 12 1
3
1 12
1 3
y g 1 ( x) x
2 2
3
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57
QUESTION 27
y 3
x2
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58
QUESTION 28
28.1 0 x 2 3x 4 equating to 0
factors
0 ( x 4)( x 1)
x-values
x 4 or x 1 length of AC (4)
AC 5 units
28.2 D(0 ; 4) answer
28.3 f ( x) x 3x 4
2 0 2x 3
3
f ( x) 2 x 3 x (2)
2
0 2x 3
3
x
2
Alternatively:
3 3 substitution in formula
x 3
2(1) 2 x (2)
2
28.4 y ab x q q 4
The horizontal asymptote is y 4 . Substitute (0 ; 1)
q 4 a 5
Substitute ( 1 ; 0)
y ab x 4
5
Substitute (0 ; 1) : b (5)
4
1 ab0 4
5 a(1)
a 5
y 5b x 4
Substitute ( 1 ; 0) :
0 5b 1 4
5
4
b
4b 5
5
b
4
28.5 k 4 answer (2)
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59
QUESTION 29
y h( x) g 1 ( x 2)
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