• Reading time – 10 minutes • Working time – 2 hours • Write using black pen • Calculators approved by NESA may be used • A reference sheet is provided at the back of this paper • In Questions 11–14, show relevant mathematical reasoning and/or calculations Section I – 10 marks (pages 2–6) • Attempt Questions 1–10 • Allow about 15 minutes for this section Section II – 60 marks (pages 7–12) • Attempt Questions 11–14 • Allow about 1 hour and 45 minutes for this section General Instructions Total marks: 70 Mathematics Extension 1 NSW Education Standards Authority Sample HIGHER SCHOOL CERTIFICATE EXAMINATION
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• Reading time – 10 minutes• Working time – 2 hours• Write using black pen• Calculators approved by NESA may be used• A reference sheet is provided at the back of this paper• In Questions 11–14, show relevant mathematical reasoning
and/ or calculations
Section I – 10 marks (pages 2–6)• Attempt Questions 1–10• Allow about 15 minutes for this section
Section II – 60 marks (pages 7–12)• Attempt Questions 11–14• Allow about 1 hour and 45 minutes for this section
General Instructions
Total marks: 70
Mathematics Extension 1
NSW Education Standards Authority
Sample HIGHER SCHOOL CERTIFICATE EXAMINATION
– 2 –
Section I
10 marksAttempt Questions 1–10Allow about 15 minutes for this section
Use the multiple-choice answer sheet for Questions 1–10.
1 What is the angle between the vectors 7
1⎛⎝⎜
⎞⎠⎟
and –1
1⎛⎝⎜
⎞⎠⎟
?
A. cos–1(0.6)
B. cos–1(0.06)
C. cos–1(– 0.06)
D. cos–1(– 0.6)
2 The diagram shows a grid of equally spaced lines. The vector OH = h and the vector
OA = a . The point P is halfway between B and C.
A
D
O G H
E F
B C
P
Which expression represents the vector OP?
A. − 12
a − 14
h
B.14
a –12
h
C. a + 14
h
D. a + 34
h
– 3 –
3 Given that cos q – 2 sin q + 2 = 0, which of the following shows the two possible values
for tanθ2
?
A. – 3 or –1
B. – 3 or 1
C. –1 or 3
D. 1 or 3
4 What is the derivative of tan−1 x2
?
A. 1
2( 4 + x 2 )
B. 1
4 + x 2
C. 2
4 + x 2
D. 4
4 + x 2
– 4 –
5 The slope field for a first order differential equation is shown.
3
2
1
–1
–4 4 x
y
–3 3–2 2–1 1O
–2
–3
Which of the following could be the differential equation represented?
A. dydx
= x3y
B. dydx
= – x3y
C. dydx
= xy3
D. dydx
= – xy3
– 5 –
6 Let P(x) = qx3 + rx2 + rx + q where q and r are constants, q ≠ 0. One of the zeros of P(x) is −1.
Given that a is a zero of P(x), a ≠ −1, which of the following is also a zero?
A. − 1a
B. − qa
C. 1a
D. qa
7 Each of the students in an athletics team is randomly allocated their own locker from a row of 100 lockers.
What is the smallest number of students in the team that guarantees that two students are allocated consecutive lockers?
A. 26
B. 34
C. 50
D. 51
8 A team of 11 students is to be chosen from a group of 18 students. Among the 18 students are 3 students who are left-handed.
What is the number of possible teams containing at least 1 student who is left-handed?
A. 19 448
B. 30 459
C. 31 824
D. 58 344
– 6 –
9 A stone drops into a pond, creating a circular ripple. The radius of the ripple increases from 0 cm at a constant rate of 5 cm s−1.
At what rate is the area enclosed within the ripple increasing when the radius is 15 cm?
A. 25p cm2 s−1
B. 30p cm2 s−1
C. 150p cm2 s−1
D. 225p cm2 s−1
10 The graph of the function y = sin–1(x – 4) is transformed by being dilated horizontally with a scale factor of 2 and then translated to the right by 1.
What is the equation of the transformed graph?
A. y = sin−1 x − 92
⎛⎝
⎞⎠
B. y = sin−1 x −102
⎛⎝
⎞⎠
C. y = sin−1 2x − 6( )
D. y = sin−1 2x − 5( )
– 7 –
Section II
60 marksAttempt Questions 11–14Allow about 1 hour and 45 minutes for this section
Answer each question in the appropriate writing booklet. Extra writing booklets are available.
In Questions 11–14, your responses should include relevant mathematical reasoning and/or calculations.
Question 11 (15 marks) Use the Question 11 Writing Booklet.
(a) A particle is fired from the origin O with initial velocity 18 m s–1 at an angle 60° to the horizontal.
The equations of motion are d2x
dt2= 0 and
d2y
dt2= –10 .
(i) Show that x = 9t. (ii) Show that y = 9 3t − 5t2 . (iii) Hence find the Cartesian equation for the trajectory of the particle.
(b) A function â ( x ) is given by x2 + 4x + 7 .
(i) Explain why the domain of the function â ( x ) must be restricted if â ( x ) is to have an inverse function.
(ii) Give the equation for â –1( x ) if the domain of â ( x ) is restricted to x ≥ –2.
(iii) State the domain and range of â –1( x ), given the restriction in part (ii).
(iv) Sketch the curve y = â –1( x ).
Question 11 continues on page 8
1
2
1
1
2
2
2
– 8 –
Question 11 (continued)
(c) The trajectories of particles in a fluid are described by the differential equation
dydx
= 14
(y – 2)(y – x).
The slope field for the differential equation is sketched below.
y
x
1
O
2
3
–5 –4 –3 –2 –1
–1
1 2 3 4 5
(i) Identify any solutions of the form y = k, where k is a constant.
(ii) Draw a sketch of the trajectory of a particle in the fluid which passes through the point (–3,1) and describe the trajectory as x ± ∞.
End of Question 11
1
3
– 9 –
Question 12 (15 marks) Use the Question 12 Writing Booklet.
(a) A recent census showed that 20% of the adults in a city eat out regularly.
(i) A survey of 100 adults in this city is to be conducted to find the proportion who eat out regularly. Show that the mean and standard deviation for the distribution of sample proportions of such surveys are 0.2 and 0.04 respectively.
(ii) Use the extract shown from a table giving values of P (Z < z), where z has a standard normal distribution, to estimate the probability that a survey of 100 adults will find that at most 15 of those surveyed eat out regularly.
(i) Find the component of the force F in the direction of the line .
(ii) What is the component of the force F in the direction perpendicular to the line?
(c) The points A and B are fixed points in a plane and have position vectors a and b respectively.
The point P with position vector also lies in the plane and is chosen so that APB = 90°.
(i) Explain why (a – ) . (b – ) = 0.
(ii) Let m = 12
(a + b) denote the position vector of M, the midpoint of A and B.
Using the properties of vectors, show that p − m 2 is independent of and find its value.
(iii) What does the result in part (ii) prove about the point P?
(d) Use mathematical induction to prove that 23n – 3n is divisible by 5 for n ≥ 1.
2
2
2
1
1
3
1
3
– 10 –
Question 13 (14 marks) Use the Question 13 Writing Booklet.
(a) Using the substitution x = sin2 q, or otherwise, evaluate x
1− xdx
0
12⌠
⌡⎮ .
(b) A device playing a signal given by x = 2sin t + cos t produces distortion whenever x ≥ 1.5.
For what fraction of the time will the device produce distortion if the signal is played continuously?
(c) (i) Prove the trigonometric identity cos 3 q = 4 cos3q – 3 cos q.
(ii) Hence find expressions for the exact values of the solutions to the equation 8x3 – 6x = 1.
3
4
3
4
– 11 –
Question 14 (16 marks) Use the Question 14 Writing Booklet.
(a) (i) Sketch the graph of y = x cos x for –p ≤ x ≤ p and hence explain why
x cos x dx = 0.−π
2
π2⌠
⌡⎮
(ii) Consider the volume of the solid of revolution produced by rotating about the x-axis the shaded region between the graph of y = x – cos x, the
x-axis and the lines x = – p
2 and x =
p
2 .
p
2p
2–
–1
1
2 y = x – cosx
y
xO
Using the results of part (i), or otherwise, find the volume of the solid.
(b) The population of foxes on an island is modelled by the logistic equation dydt
= y(1 – y), where y is the fraction of the island’s carrying capacity reached
after t years.
At time t = 0, the population of foxes is estimated to be one-quarter of the island’s carrying capacity.
(i) Use the substitution y = 1
1 – w to transform the logistic equation to
dwdt
= –w.
(ii) Using the solution of dwdt
= –w, find the solution of the logistic equation
for y satisfying the initial conditions.
(iii) How long will it take for the fox population to reach three-quarters of the island’s carrying capacity?
Question 14 continues on page 12
3
3
2
2
2
– 12 –
Question 14 (continued)
(c) The diagram below is a sketch of the graph of the function y = â ( x ).
y ƒ x
(0,7.5)
(0.5,2.5)
8
6
4
2
–1 1 2 3 4 5
–2 (2,–1.75)
y
xO
(i) Sketch the graph of y = 1ƒ x( )
.
Your sketch should show any asymptotes and intercepts, together with the location of the points corresponding to the labelled points on the original sketch.
• Refers to horizontal line test, or equivalent merit 1
Sample answer:
ƒ x( ) = x2 + 4x + 7 is a parabola. Therefore, for each value of ƒ x( ) in the range (except at the turning point), there are two x-values. (A horizontal line will cut the graph twice.) ∴ If x and y are swapped, each x in the domain will have two y-values, and so the inverse will
not be a function. Question 11 (b) (ii) Criteria Marks • Provides correct solution 2 • Swaps x and y or equivalent merit 1
Sample answer:
ƒ x( ) = x2 + 4x + 7 x ≥ −2
= x + 2( )2 + 3
ƒ −1 x( ): x = y + 2( )2 + 3
x − 3 = y + 2( )2
y + 2 = x − 3 − x − 3 is discarded as y must be ≥ −2( )y = x − 3( ) − 2
• Provides correct solution 3 • Attempts to use a double angle result, or equivalent merit 2 • Obtains correct integrand in terms of θ, or equivalent merit 1
• Provides correct sketch and explanation 3 • Provides correct sketch, or equivalent merit 2 • Provides a sketch that is an odd function or has three zeros, or equivalent
• Provides correct sketch including location information 3 • Provides correct shape and asymptotes 2 • Provides a sketch with asymptotes at x = 1, x = 3 and y = 0 1
Sample answer:
Question 14 (c) (ii) Criteria Marks
• Identifies that the equation has (at least) five solutions 1
Sample answer: The equation has at least five solutions. (It might have more depending on the behaviour outside the region shown in the sketch in the question.)