functions math studies

35
1 1. At Jumbo's Burger Bar, Jumbo burgers cost £J each and regular cokes cost £C each. Two Jumbo burgers and three regular cokes cost £5.95. (a) Write an equation to show this. (b) If one Jumbo Burger costs £2.15, what is the cost, in pence, of one regular coke? (Total 4 marks) 2. In an experiment researchers found that a specific culture of bacteria increases in number according to the formula N = 150 × 2 t , where N is the number of bacteria present and t is the number of hours since the experiment began. Use this formula to calculate (a) the number of bacteria present at the start of the experiment; (b) the number of bacteria present after 3 hours; (c) the number of hours it would take for the number of bacteria to reach 19 200. (Total 4 marks) 3. The graph of y = x 2 2x 3 is shown on the axes below. x y –4 –3 –2 –1 0 1 2 3 4 5 6 20 10 (a) Draw the graph of y = 5 on the same axes. (b) Use your graph to find: (i) the values of x when x 2 2x 3 = 5 (ii) the value of x that gives the minimum value of x 2 2x 3 (Total 4 marks) 4. The profit (P) in Swiss Francs made by three students selling homemade lemonade is modelled by the function P = 20 1 x 2 + 5x 30 where x is the number of glasses of lemonade sold.

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Page 1: Functions Math Studies

1

1. At Jumbo's Burger Bar, Jumbo burgers cost £J each and regular cokes cost £C each. Two Jumbo

burgers and three regular cokes cost £5.95.

(a) Write an equation to show this.

(b) If one Jumbo Burger costs £2.15, what is the cost, in pence, of one regular coke?

(Total 4 marks)

2. In an experiment researchers found that a specific culture of bacteria increases in number according to

the formula

N = 150 × 2t,

where N is the number of bacteria present and t is the number of hours since the experiment began.

Use this formula to calculate

(a) the number of bacteria present at the start of the experiment; (b) the number of bacteria present after 3 hours;

(c) the number of hours it would take for the number of bacteria to reach 19 200.

(Total 4 marks)

3. The graph of y = x2 – 2x – 3 is shown on the axes below.

x

y

–4 –3 –2 –1 0 1 2 3 4 5 6

20

10

(a) Draw the graph of y = 5 on the same axes. (b) Use your graph to find:

(i) the values of x when x2 – 2x – 3 = 5

(ii) the value of x that gives the minimum value of x2 – 2x – 3

(Total 4 marks)

4. The profit (P) in Swiss Francs made by three students selling homemade lemonade is modelled by the

function

P = – 20

1 x

2 + 5x – 30

where x is the number of glasses of lemonade sold.

Page 2: Functions Math Studies

2

(a) Copy and complete the table below

x 0 10 20 30 40 50 60 70 80 90

P 15 90 75 50

(3)

(b) On graph paper draw axes for x and P, placing x on the horizontal axis and P on the vertical

axis. Use suitable scales. Draw the graph of P against x by plotting the points. Label your

graph. (5)

(c) Use your graph to find

(i) the maximum possible profit; (1)

(ii) the number of glasses that need to be sold to make the maximum profit; (1)

(iii) the number of glasses that need to be sold to make a profit of 80 Swiss Francs; (2)

(iv) the amount of money initially invested by the three students. (1)

(d) The three students Baljeet, Jane and Fiona share the profits in the ratio of 1 : 2 : 3 respectively.

If they sold 40 glasses of lemonade, calculate Fiona's share of the profits. (2)

(Total 15 marks)

5. The perimeter of this rectangular field is 220 m. One side is x m as shown.

x m

W m

(a) Express the width (W) in terms of x.

(b) Write an expression, in terms of x only, for the area of the field.

(c) If the length (x) is 70 m, find the area.

(Total 4 marks) 6. Angela needs $4000 to pay for a car. She was given two options by the car seller.

Option A: Outright Loan

A loan of $4000 at a rate of 12% per annum compounded monthly.

(a) Find

(i) the cost of this loan for one year; (2)

(ii) the equivalent annual simple interest rate. (2)

Option B: Friendly Credit Terms

Page 3: Functions Math Studies

3

A 25% deposit, followed by 12 equal monthly payments of $ 287.50.

(b) (i) How much is to be paid as a deposit under this option? (1)

(ii) Find the cost of the loan under Friendly Credit Terms. (2)

(c) Give a reason why Angela might choose

(i) Option A

(ii) Option B (2)

To help Angela, her employer agrees to give her an interest free loan of $4000 to buy the car. The

employer is to recover the money by making the following deductions from Angela's salary:

$x in the first month,

$y every subsequent month.

The total deductions after 20 months is $1540 and after 30 months it is $2140.

(d) Find x and y. (4)

(e) How many months will it take for Angela to completely pay off the $4000 loan? (2)

(Total 15 marks) 7. Vanessa wants to rent a place for her wedding reception. She obtains two quotations.

(a) The local council will charge her £30 for the use of the community hall plus £ 10 per guest.

(i) Copy and complete this table for charges made by the local council.

Number of guests (N) 10 30 50 70 90

Charges (C) in £

(2)

(ii) On graph paper, using suitable scales, draw and label a graph showing the charges. Take

the horizontal axis as the number of guests and the vertical axis as the charges. (3)

(iii) Write a formula for C, in terms N, that can be used by the local council to calculate their

charges. (1)

(b) The local hotel calculates charges for their conference room using the formula:

C = 2

5N + 500

where C is the charge in £ and N is the number of guests.

(i) Describe, in words only, what this formula means. (2)

(ii) Copy and complete this table for the charges made by the hotel.

Page 4: Functions Math Studies

4

Number of guests (N) 0 20 40 80

Charges (C) in £

(2)

(iii) On the same axes used in part (a)(ii), draw this graph of C. Label your graph clearly. (2)

(c) Explain, briefly, what the two graphs tell you about the charges made. (2)

(d) Using your graphs or otherwise, find

(i) the cost of renting the community hall if there are 87 guests; (2)

(ii) the number of guests if the hotel charges £650; (2)

(iii) the difference in charges between the council and the hotel if there are 82 guests at the

reception. (2)

(Total 20 marks)

8. The diagram shows the graph of y = x2 – 2x – 8. The graph crosses the x-axis at the point A, and has a

vertex at B.

y

x

B

A O

(a) Factorise x2 – 2x – 8.

(b) Write down the coordinates of each of these points

(i) A;

(ii) B.

(Total 4 marks) 9. The costs charged by two taxi services are represented by the two parallel lines on the following

graph. The Speedy Taxi Service charges $1.80, plus 10 cents for each kilometre.

Page 5: Functions Math Studies

5

2.60

2.40

2.20

2.00

1.80

1.60

1.40

1.20

1.00

c

k0 2 4 6 8

distance (km)

cost ($)

Speedy Taxi Service

Economic Taxi Service

(a) Write an equation for the cost, c, in $, of using the Economic Taxi Service for any number of

kilometres, k. (b) Bruce uses the Economic Taxi Service.

(i) How much will he pay for travelling 7 km ?

(ii) How far can he travel for $2.40 ?

(Total 4 marks) 10. The following diagrams show the graphs of five functions.

Page 6: Functions Math Studies

6

I

III

II

IV

V

y

y

y

y

y

x

x

x

x

x

1 2

1 2

1 2

1 2

1 2

–2

–2

–2

–2

–2

–1

–1

–1

–1

–1

2

2

2

2

2

1

–1

–2

1

–1

–2

1

–1

–2

1

–1

–2

1

–1

–2

Each of the following sets represents the range of one of the functions of the graphs on the previous

page.

(a) {y y }

(b) {y y 2}

(c) {y y > 0} (d) {y 1 ≤ y ≤ 2}

Write down which diagram is linked to each set.

(Total 4 marks)

11. (a) For y = 0.5 cos 0.5 x, find

(i) the amplitude;

(ii) the period.

Page 7: Functions Math Studies

7

(b) Let y = –3 sin x + 2, where 90° ≤ x ≤ 270°.

By drawing the graph of y or otherwise, complete the table below for the given values of y.

x y

–1

2 -

(Total 4 marks)

12. The line L1 shown on the set of axes below has equation 3x + 4y = 24. L1 cuts the x-axis at A and cuts

the y-axis at B. Diagram not drawn to scale

y

x

B

C

AO

M

L

L

1

2

(a) Write down the coordinates of A and B. (2)

M is the midpoint of the line segment [AB].

(b) Write down the coordinates of M. (2)

The line L2 passes through the point M and the point C (0, –2).

(c) Write down the equation of L2.

(2)

Page 8: Functions Math Studies

8

(d) Find the length of

(i) MC; (2)

(ii) AC. (2)

(e) The length of AM is 5. Find

(i) the size of angle CMA; (3)

(ii) the area of the triangle with vertices C, M and A. (2)

(Total 15 marks)

13. The following diagram shows part of the graph of an exponential function f(x) = a–x

, where x .

f x( )y

x

P

0

(a) What is the range of f ?

(b) Write down the coordinates of the point P. (c) What happens to the values of f(x) as elements in its domain increase in value?

(Total 4 marks)

14. (a) A function f is represented by the following mapping diagram.

–1

0

1

2

3

–5

–2

1

4

7

Write down the function f in the form

f : x y, x {the domain of f}.

Page 9: Functions Math Studies

9

(b) The function g is defined as follows

g : x sin 15x°, {x and 0 < x ≤ 4}.

Complete the following mapping diagram to represent the function g.

(Total 4 marks)

15. Diagram 1 shows a part of the graph of y = x2.

y

x0

Diagram 1 Diagrams 2, 3 and 4 show a part of the graph of y = x

2 after it has been moved parallel to the

x-axis, or parallel to the y-axis, or parallel to one axis, then the other.

y y y

x x x0 0 0

3

2 2

3

Diagram 2 Diagram 3 Diagram 4

Write down the equation of the graph shown in

(a) Diagram 2;

(b) Diagram 3;

(c) Diagram 4. (Total 4 marks)

16. The perimeter of a rectangle is 24 metres.

(a) The table shows some of the possible dimensions of the rectangle.

Find the values of a, b, c, d and e.

Page 10: Functions Math Studies

10

Length (m) Width (m) Area (m2)

1 11 11

a 10 b

3 c 27

4 d e

(2)

(b) If the length of the rectangle is x m, and the area is A m2, express A in terms of x only.

(1)

(c) What are the length and width of the rectangle if the area is to be a maximum? (3)

(Total 6 marks) 17. Under certain conditions the number of bacteria in a particular culture doubles every 10 seconds as

shown by the graph below.

8

7

6

5

4

3

2

1

0 10 20 30

Time(seconds)

Numberof

bacteria

(a) Complete the table below.

Time (seconds) 0 10 20 30

Number of bacteria 1

(b) Calculate the number of bacteria in the culture after 1 minute.

(Total 4 marks)

18. (a) Solve the equation x2 – 5x + 6 = 0.

Page 11: Functions Math Studies

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(b) Find the coordinates of the points where the graph of y = x

2 – 5x + 6 intersects the x-axis.

(Total 4 marks) 19. The diagram below shows the graph of y = – a sin x° + c, 0 ≤ x ≤ 360.

5

4

3

2

1

0

–1

–2

–3

x

y

90 180 270 360

Use the graph to find the values of

(a) c;

(b) a.

(Total 4 marks) 20. The graph below shows part of the function y = 2 sin x + 3.

6

5

4

3

2

1

0

0º 90º 180º 270º 360º 450ºx

y

(a) Write the domain of the part of the function shown on the graph.

(b) Write the range of the part of the function shown on the graph.

Page 12: Functions Math Studies

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(Total 4 marks)

21. The diagram below shows part of the graph of y = ax2 + 4x – 3. The line x = 2 is the axis of

symmetry. M and N are points on the curve, as shown.

y

x0

N

M

x = 2

(a) Find the value of a.

(b) Find the coordinates of

(i) M;

(ii) N.

(Total 4 marks)

22. The number (n) of bacteria in a colony after h hours is given by the formula n = 1200 (30.25h

).

Initially, there are 1200 bacteria in the colony.

(a) Copy and complete the table below, which gives values of n and h.

Give your answers to the nearest hundred.

time in hours (h) 0 1 2 3 4

no. of bacteria (n) 1200 2100 2700

(2)

(b) On graph paper, draw the graph of the above function. Use a scale of 3 cm to represent 1 hour

on the horizontal axis and 4 cm to represent 1000 bacteria on the vertical axis. Label the graph

clearly. (5)

(c) Use your graph to answer each of the following, showing your method clearly.

(i) How many bacteria would there be after 2 hours and 40 minutes?

Give your answer to the nearest hundred bacteria.

(ii) After how long will there be approximately 3000 bacteria? Give your answer to the

nearest 10 minutes. (4)

(Total 11 marks)

Page 13: Functions Math Studies

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23. The velocity, vms–1

, of a kite, after t seconds, is given by

v = t3 – 4t

2 + 4t, 0 t 4.

(a) What is the velocity of the kite after

(i) one second?

(ii) half a second? (2)

(b) Calculate the values of a and b in the table below.

t 0 0.5 1 1.5 2 2.5 3 3.5 4

v 0 a 0 0.625 b 7.88 16

(2)

(c) (i) Find t

v

d

d in terms of t. Find the value of t at the local maximum and minimum values of

the function.

(ii) Explain what is happening to the function at its local maximum point.

Write down the gradient of the tangent to its curve at this point. (8)

(d) On graph paper, draw the graph of the function v = t3 – 4t

2 + 4t, 0 t 4.

Use a scale of 2 cm to represent 1 second on the horizontal axis and 2 cm to represent 2 ms–1

on the vertical axis. (5)

(e) Describe the motion of the kite at different times during the first 4 seconds.

Write down the intervals corresponding to changes in motion. (3)

The acceleration, a, of a second kite is given by the equation a = 4t – 3, 0 t 4.

(f) After 1 second, the velocity, u, of this kite, is 3 ms–1

. Write the equation for u in terms of t. (4)

(Total 24 marks)

24. The graph below shows the curve y = k(2x) + c, where k and c are constants.

0

y

x–6 –4 –2 2 4

10

–10

Find the values of c and k.

Page 14: Functions Math Studies

14

(Total 4 marks)

25. A rectangle has dimensions (5 + 2x) metres and (7 – 2x) metres.

(a) Show that the area, A, of the rectangle can be written as A = 35 + 4x – 4x2.

(1)

(b) The following is the table of values for the function A = 35 + 4x – 4x2.

x –3 –2 –1 0 1 2 3 4

A –13 p 27 35 q r 11 s

(i) Calculate the values of p, q, r and s.

(ii) On graph paper, using a scale of 1 cm for 1 unit on the x-axis and 1 cm for 5 units on the

A-axis, plot the points from your table and join them up to form a smooth curve. (6)

(c) Answer the following, using your graph or otherwise.

(i) Write down the equation of the axis of symmetry of the curve,

(ii) Find one value of x for a rectangle whose area is 27 m2.

(iii) Using this value of x, write down the dimensions of the rectangle. (4)

(d) (i) On the same graph, draw the line with equation A = 5x + 30.

(ii) Hence or otherwise, solve the equation 4x2 + x – 5 = 0.

(3)

(Total 14 marks)

26. Consider the graphs of the following functions.

(i) y = 7x + x2;

(ii) y = (x – 2)(x + 3);

(iii) y = 3x2 – 2x + 5;

(iv) y = 5 – 3x – 2x2.

Which of these graphs

(a) has a y-ntercept below the x-xis?

(b) passes through the origin?

(c) does not cross the x-xis?

(d) could be represented by the following diagram?

Page 15: Functions Math Studies

15

y

xO

(Total 8 marks) 27. The following diagram shows the lines l1 and l2, which are perpendicular to each other.

Diagram not to scale

y

x(5, 0)

(0, 7)

(0, –2)

l

l

1

2

(a) Calculate the gradient of line l1.

(b) Write the equation of line l1 in the form ax + by + d = 0 where a, b and d are integers, and a >

0. (Total 8 marks)

28. The cost c, in Australian dollars (AUD), of renting a bungalow for n weeks is given by the linear

relationship c = nr + s, where s is the security deposit and r is the amount of rent per week.

Ana rented the bungalow for 12 weeks and paid a total of 2925 AUD.

Raquel rented the same bungalow for 20 weeks and paid a total of 4525 AUD. Find the value of

(a) r, the rent per week;

(b) s, the security deposit.

(Total 8 marks)

29. The following diagram shows the graph of y = 3–x

+ 2. The curve passes through the points (0, a) and

(1, b).

Diagram not to scale

Page 16: Functions Math Studies

16

y

x

(0, ) a(1, ) b

O

(a) Find the value of

(i) a;

(ii) b.

(b) Write down the equation of the asymptote to this curve.

(Total 8 marks)

30. The graph below shows the tide heights, h metres, at time t hours after midnight, for Tahini island.

5

4

3

2

1

01 2 3 4 5 6 7 8

Number of hours after midnight

Tide heights for Tahini

Hei

gh

t in

met

res

h

t

(a) Use the graph to find

(i) the height of the tide at 03:15;

(ii) the times when the height of the tide is 3.5 metres. (3)

(b) The best time to catch fish is when the tide is below 3 metres. Find this best time, giving your

answer as an inequality in t. (3)

Due to the location of Tahini island, there is very little variation in the pattern of tidal heights. The

maximum tide height is 4.5 metres and the minimum tide height is 1.5 metres. The height h can be

modelled by the function

Page 17: Functions Math Studies

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h(t) = acos(bt°) + 3.

(c) Use the graph above to find the values of the variables a and b. (4)

(d) Hence calculate the height of the tide at 13:00. (3)

(e) At what time would the tide be at its lowest point in the second 8 hour period? (2)

(Total 15 marks)

31. The diagram below shows a part of the graph of y = ax. The graph crosses the y-axis at the point P.

The point Q (4, 16) is on the graph.

y

xO

P

Q (4, 16)

Find

(a) the coordinates of the point P;

(b) the value of a.

(Total 8 marks) 32. The diagrams below show the graphs of two functions, y = f(x), and y = g(x).

(b)(a) yy

x

x

2

1

0 1 2

1

0.5

–0.5

–1

–1.5

1.5y f x = ( ) y g x = ( )

–360º 360º–180º 180º

State the domain and range of

(a) the function f;

(b) the function g.

(Total 8 marks) 33. The diagram below represents a stopwatch. This is a circle, centre O, inside a square of side

6 cm, also with centre O. The stopwatch has a minutes hand and a seconds hand. The seconds hand,

with end point T, is shown in the diagram, and has a radius of 2 cm.

Page 18: Functions Math Studies

18

A

D

T

O

B

C

6 cm

r

qp

(a) When T is at the point A, the shortest distance from T to the base of the square is p. Calculate

the value of p. (2)

(b) In 10 seconds, T moves from point A to point B. When T is at the point B, the shortest distance

from T to the base of the square is q. Calculate

(i) the size of angle AOB;

(ii) the distance OD;

(iii) the value of q. (5)

(c) In another 10 seconds, T moves from point B to point C. When T is at the point C, the shortest

distance from T to the base of the square is r. Calculate the value of r. (4)

Let d be the shortest distance from T to the base of the square, when the seconds hand has moved

through an angle . The following table gives values of d and .

Angle 0° 30° 60° 90° 120° 150° 180° 210° 2400 270° 300° 330 360°

Distance p 4.7 q 3 r 1.3 1 1.3 r 3 q 4.7 p

d The graph representing this information is as follows.

d

p

q

r

0º 30º 60º 90º 120º 150º 180º 210º 240º 270º 300º 330º 360ºangle

The equation of this graph can be written in the form d = c + k cos().

(d) Find the values of c and k. (4)

Page 19: Functions Math Studies

19

(Total 15 marks)

34. The conversion formula for temperature from the Fahrenheit (F) to the Celsius (C) scale is given by C

= 9

)32–(5 F.

(a) What is the temperature in degrees Celsius when it is 50° Fahrenheit? There is another temperature scale called the Kelvin (K) scale.

The temperature in degrees Kelvin is given by K = C + 273.

(b) What is the temperature in Fahrenheit when it is zero degrees on the Kelvin scale?

(Total 8 marks)

35. The four diagrams below show the graphs of four different straight lines, all drawn to the same scale.

Each diagram is numbered and c is a positive constant.

x

x

x

x

y

y

y

y

c

c

c

c

Number 1

Number 2

Number 3

Number 4

0

0

0

0 In the table below, write the number of the diagram whose straight line corresponds to the equation in

the table.

Equation Diagram number

y = c

y = – x + c

y = 3 x + c

y = 3

1 x + c

(Total 8 marks)

36. The diagram shows a chain hanging between two hooks A and B.

The points A and B are at equal heights above the ground. P is the lowest point on the chain. The

ground is represented by the x-axis. The x-coordinate of A is –2 and the x-coordinate of B is 2. Point

P is on the y-axis. The shape of the chain is given by y = 2x + 2

–x where –2 ≤ x ≤ 2.

Page 20: Functions Math Studies

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Chain

Ground

–2 0 2 x

yA B

P

(a) Calculate the height of the point P. (b) Find the range of y. Write your answer as an interval or using inequality symbols.

(Total 8 marks)

37. The figure below shows part of the graph of a quadratic function y = ax2 + 4x + c.

8

6

4

2

–2 –1 1 2 3 4 x

y

(a) Write down the value of c.

(b) Find the value of a. (c) Write the quadratic function in its factorised form.

(Total 8 marks)

38. The figure below shows a hexagon with sides all of length 4 cm and with centre at O. The interior

angles of the hexagon are all equal.

Page 21: Functions Math Studies

21

A

B

CD

E

F

O

4 cm

The interior angles of a polygon with n equal sides and n equal angles (regular polygon) add up to (n

– 2) × 180°.

(a) Calculate the size of angle A B̂ C.

(b) Given that OB = OC, find the area of the triangle OBC. (c) Find the area of the whole hexagon.

(Total 8 marks)

39. The number of bacteria (y) present at any time is given by the formula:

y = 15 000e–025t

, where t is the time in seconds and e = 2.72 correct to 3 s.f.

(a) Calculate the values of a, b and c to the nearest hundred in the table below:

Time in seconds (t) 0 1 2 3 4 5 6 7 8

Amount of bacteria (y)

(nearest hundred)

a 11700 9100 7100 b 4300 3300 2600 c

(3)

(b) On graph paper using 1 cm for each second on the horizontal axis and 1 cm for each thousand

on the vertical axis, draw and label the graph representing this information. (5)

(c) Using your graph, answer the following questions:

(i) After how many seconds will there be 5000 bacteria? Give your answer correct to the

nearest tenth of a second.

(ii) How many bacteria will there be after 6.8 seconds? Give your answer correct to the

nearest hundred bacteria.

(iii) Will there be a time when there are no bacteria left? Explain your answer. (6)

(Total 14 marks)

40. Consider the function f (x) = x3 – 4x

2 – 3x + 18

(a) (i) Find f (x).

(ii) Find the coordinates of the maximum and minimum points of the function. (10)

(b) Find the values of f (x) for for a and b in the table below:

Page 22: Functions Math Studies

22

x –3 –2 –1 0 1 2 3 4 5

f (x) –36 a 16 b 12 4 0 6 28

(2)

(c) Using a scale of 1 cm for each unit on the x-axis and 1 cm for each 5 units on the y-axis, draw

the graph of f(x) for –3 ≤ x ≤ 5. Label clearly. (5)

(d) The gradient of the curve at any particular point varies. Within the interval –3 ≤ x ≤ 5, state all

the intervals where the gradient of the curve at any particular point is

(i) negative,

(ii) positive. (3)

(Total 20 marks)

41. The graph of the function f : x 30x – 5x2 is given in the diagram below.

Diagramnot to scale

f x( )

xO A

(a) Factorize fully 30x – x2.

(b) Find the coordinates of the point A. (c) Write down the equation of the axis of symmetry.

(Total 8 marks) 42. Consider the function f (x) = 2sinx – 1 where 0 ≤ x ≤ 720°.

(a) Write down the period of the function.

(b) Find the minimum value of the function.

(c) Solve f (x) = l.

(Total 8 marks) 43. The diagrams below are sketches of some of the following functions.

(i) y = ax (ii) y = x

2 – a (iii) y = a – x

2

(iv) y = a – x (v) y = x – a

Page 23: Functions Math Studies

23

x

x

x

x

y

y

y

y

(a)

(c)

(b)

(d)DIAGRAMS NOTTO SCALE

Complete the table to match each sketch to the correct function.

Sketch Function

(a)

(b)

(c)

(d)

(Total 8 marks)

44. The area, A m2, of a fast growing plant is measured at noon (12:00) each day. On 7 July the area was

100 m2. Every day the plant grew by 7.5%. The formula for A is given by

A = 100 (1.075)t

where t is the number of days after 7 July. (on 7 July, t = 0)

The graph of A = 100(1.075)t is shown below.

400

300

200

100

–6 –4 –2 0 2 4 6 8 10 12 14 16 18

A

t

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7 July

(a) What does the graph represent when t is negative? (2)

(b) Use the graph to find the value of t when A = 178. (1)

(c) Calculate the area covered by the plant at noon on 28 July. (3)

(Total 6 marks)

45. The graph of the function y = x2 – x – 2 is drawn below.

x

y

A B

C

0

(a) Write down the coordinates of the point C.

(b) Calculate the coordinates of the points A and B.

(Total 8 marks)

46. The curve shown in the figure below is part of the graph of the function, f (x) = 2 + sin (2x), where x

is measured in degrees.

4

3.5

3

2.5

2

1.5

1

0.5

–0.5

0–180–150–120 –90 –60 –30 30 60 90 120 150 180 210 240

f x( )

x

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25

(a) Find the range of f (x).

(b) Find the amplitude of f (x).

(c) Find the period of f (x). (d) If the function is changed to f (x) = 2 + sin (4x) what is the effect on the period, compared to

the period of the original function?

(Total 8 marks)

47. A student has drawn the two straight line graphs L1 and L2 and marked in the angle between them as

a right angle, as shown below. The student has drawn one of the lines incorrectly.

3

2

1

–1

–4 –3 –2 –1 0 1 2 3 4 x

y

90°

L

L

2

1

Consider L1 with equation y = 2x + 2 and L2 with equation y = –4

1x + 1.

(a) Write down the gradients of L1 and L2 using the given equations.

(b) Which of the two lines has the student drawn incorrectly? (c) How can you tell from the answer to part (a) that the angle between L1 and L2 should not be

90°?

(d) Draw the correct version of the incorrectly drawn line on the diagram.

(Total 8 marks)

48. The following table gives the postage rates for sending letters from the Netherlands. All prices are

given in Euros (€).

Destination Weight not more than 20 g Each additional 20 g or part of 20 g

Within the Netherlands

(zone 1) € 0.40 € 0.35

Other destinations

within Europe (zone 2) € 0.55 € 0.50

Outside Europe

(zone 3) € 0.80 € 0.70

(a) Write down the cost of sending a letter weighing 15 g from the Netherlands to a destination

within the Netherlands (zone 1).

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26

(b) Find the cost of sending a letter weighing 35 g from the Netherlands to a destination in France

(zone 2). (c) Find the cost of sending a letter weighing 50 g from the Netherlands to a destination in the

USA (zone 3).

(Total 8 marks)

49. Write down the domain and range of the following functions.

(a)

4

3

2

1

–1

–2

–3 –2 –1 0 1 2 3 4 x

y

(b)

4

3

2

1

–1

–2

–3 –2 –1 0 1 2 3 4 x

y

(Total 8 marks)

50. The graph of the function f (x) = x2 – 2x – 3 is shown in the diagram below.

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A B

C

0

y

x

Diagram not to scale

(a) Factorize the expression x2 – 2x – 3.

(b) Write down the coordinates of the points A and B.

(c) Write down the equation of the axis of symmetry.

(d) Write down the coordinates of the point C, the vertex of the parabola.

(Total 8 marks) 51. The diagram shows the graph of y = sin ax + b.

30° 60° 90° 120° 150° 180° 210° 240° 270° 300° 330° 360°

2

1

0 x

y

(a) Using the graph, write down the following values

(i) the period;

(ii) the amplitude;

(iii) b.

(b) Calculate the value of a.

(Total 8 marks) 52. The graph below shows the temperature of a liquid as it is cooling.

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100

90

80

70

60

50

40

30

20

10

05 10 15 20 25 30 35 40 45 50 55 60 x

y

Time in minutes

Tem

per

atu

re (

°C)

(a) Write down the temperature after 5 minutes.

(b) After how many minutes is the temperature 50°C?

The equation of the graph for all positive x can be written in the form y = 100(5–002x

).

(c) Calculate the temperature after 80 minutes. (d) Write down the equation of the asymptote to the curve.

(Total 8 marks)

53. Two functions are defined as follows

f (x) =

6for6–

60for–6

xx

xx

g (x) = 2

1x

(a) Draw the graphs of the functions f and g in the interval 0 ≤ x ≤ 14, 0 ≤ y ≤ 8 using a scale of 1

cm to represent 1 unit on both axes.

(5)

(b) (i) Mark the intersection points A and B of f (x) and g (x) on the graph.

(ii) Write down the coordinates of A and B. (3)

(c) Calculate the midpoint M of the line AB. (2)

(d) Find the equation of the straight line which joins the points M and N.

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(4)

(Total 14 marks) 54. The diagram shows a point P, 12.3 m from the base of a building of height h m. The angle measured

to the top of the building from point P is 63°.

12.3

63°P

h m

(a) Calculate the height h of the building.

Consider the formula h = 4.9t2, where h is the height of the building and t is the time in seconds to fall

to the ground from the top of the building.

(b) Calculate how long it would take for a stone to fall from the top of the building to the ground.

(Total 6 marks)

55. (a) Represent the function y = 2x2 – 5, where x {–2, –1, 0, 1, 2, 3} by a mapping diagram.

x y

(b) List the elements of the domain of this function. (c) List the elements of the range of this function.

(Total 6 marks)

56. It is thought that a joke would spread in a school according to an exponential model

N = 4 × (1.356)0.4t

, t 0; where N is the number of people who have heard the joke, and t is the time

in minutes after the joke is first told.

(a) How many people heard the joke initially?

(b) How many people had heard the joke after 16 minutes?

There are 1200 people in the school.

(c) Estimate how long it would take for everybody in the school to hear this joke.

(Total 6 marks)

, 57. (a) Write 2

3

x in the form 3x

a where a .

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(b) Hence differentiate y = 2

3

x giving your answer in the form

cx

b— where c

+.

(Total 6 marks)

58. (a) Sketch the graph of the function y = 2x2 – 6x + 5.

(b) Write down the coordinates of the local maximum or minimum of the function.

(c) Find the equation of the axis of symmetry of the function. (Total 6 marks)

59. (a) Sketch a graph of y = x

x

2 for –10 ≤ x ≤ 10.

(b) Hence write down the equations of the horizontal and vertical asymptotes. (Total 6 marks)

60.

1

–1

2

–2

–3

3

0

1

4

9

0

4

5A B

16

f

The diagram shows a function f, mapping members of set A to members of set B.

(a) (i) Using set notation, write down all members of the domain of f.

(ii) Using set notation, write down all members of the range of f.

(iii) Write down the equation of the function f.

The equation of a function g is g(x) = x2 +1. The domain of g is .

(b) Write down the range of g. (Total 6 marks)

61. Below is a graph of the function y = a + b sin(cx) where a, b and c are positive integers and x is

measured in degrees.

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31

0 50 100 150 200 250 300 350

7

6

5

4

3

2

x

y

Find the values of a, b and c. (Total 6 marks)

62. (a) Sketch the graph of the function f : x 1 + 2sinx, where x , –360° ≤ x ≤ 360°. (4)

(b) Write down the range of this function for the given domain. (2)

(c) Write down the amplitude of this function. (1)

(d) On the same diagram sketch the graph of the function g : x sin 2x, where x ,

–360° ≤ x ≤ 360°. (4)

(e) Write down the period of this function. (1)

(f) Use the sketch graphs drawn to find the number of solutions to the equation

f (x) = g (x) in the given domain. (1)

(g) Hence solve the equation 1 + 2 sin x = sin 2x for 0° ≤ x ≤ 360°. (4)

(Total 17 marks)

63. (a) On the same graph sketch the curves y = x2 and y = 3 –

x

1 for values of x from 0 to 4 and

values of y from 0 to 4. Show your scales on your axes. (4)

(b) Find the points of intersection of these two curves. (4)

(c) (i) Find the gradient of the curve y = 3 – x

1 in terms of x.

(ii) Find the value of this gradient at the point (1, 2). (4)

(d) Find the equation of the tangent to the curve y = 3 – x

1 at the point (1, 2).

(3)

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(Total 15 marks)

64. The functions f and g are defined by

f : x x

x 4, x , x 0

g : x x, x

(a) Sketch the graph of f for –10 ≤ x ≤ 10. (4)

(b) Write down the equations of the horizontal and vertical asymptotes of the function f. (4)

(c) Sketch the graph of g on the same axes. (2)

(d) Hence, or otherwise, find the solutions of x

x 4 = x.

(4)

(e) Write down the range of function f. (2)

(Total 16 marks)

65. The figure below shows the graphs of the functions y = x2 and y = 2

x for values of x between –2 and 5.

The points of intersection of the two curves are labelled as B, C and D.

y

x

C

A

B

D

–2 –1 1 2 3 4 5

20

15

10

5

(a) Write down the coordinates of the point A. (2)

(b) Write down the coordinates of the points B and C. (2)

(c) Find the x-coordinate of the point D. (1)

(d) Write down, using interval notation, all values of x for which 2x ≤ x

2.

(3)

Page 33: Functions Math Studies

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(Total 8 marks)

66. At the circus a clown is swinging from an elastic rope. A student decides to investigate the motion of

the clown. The results can be shown on the graph of the function f (x) = (0.8x)(5sin100x), where x is

the horizontal distance in metres.

(a) Sketch the graph of f (x) for 0 ≤ x ≤ 10 and –3 ≤ f (x) ≤ 5. (5)

(b) Find the coordinates of the first local maximum point. (2)

(c) Find the coordinates of one point where the curve cuts the y-axis. (1)

Another clown is fired from a cannon. The clown passes through the points given in the table below:

Horizontal distance (x) Vertical distance (y)

0.00341 0.0102

0.0238 0.0714

0.563 1.69

1.92 5.76

3.40 10.2

(d) Find the correlation coefficient, r, and comment on the value for r. (3)

(e) Write down the equation of the regression line of y on x. (2)

(f) Sketch this line on the graph of f (x) in part (a). (1)

(g) Find the coordinates of one of the points where this line cuts the curve. (2)

(Total 16 marks)

67. The equation M = 90 × 2–t/20

gives the amount, in grams, of radioactive material held in a laboratory

over t years.

(a) What was the original mass of the radioactive material?

The table below lists some values for M.

t 60 80 100

M 11.25 v 2.8125

(b) Find the value of v. (c) Calculate the number of years it would take for the radioactive material to have a mass of 45

grams.

(Total 8 marks)

68. The diagram below shows the graph of y = c + kx – x2, where k and c are constants.

Page 34: Functions Math Studies

34

O

Q

P(5, 0) x

y

(a) Find the values of k and c. (b) Find the coordinates of Q, the highest point on the graph.

(Total 8 marks)

69. The graphs of three trigonometric functions are drawn below. The x variable is measured in degrees,

with –360° ≤ x ≤ 360°. The amplitude 'a' is a positive constant with 0 < a ≤ 1.

2

90

90

90

180

180

180

270

270

270

360

360

360

x

x

y

Graph A Graph B

Graph C

0

0

a

–a

a

–a (a) Write the letter of the graph next to the function representing that graph in the box below.

FUNCTION GRAPH

y = acos(x)

y = asin(2x)

y = 2 + asin(x)

(b) State the period of the function shown in graph B.

(c) State the range of the function 2 + asin(x) in terms of the constant a.

(Total 8 marks)

70. A small manufacturing company makes and sells x machines each month. The monthly cost C, in

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35

dollars, of making x machines is given by

C (x) = 2600 + 0.4x2.

The monthly income I, in dollars, obtained by selling x machines is given by

I (x) = 150x – 0.6x2.

(a) Show that the company's monthly profit can be calculated using the quadratic function

P (x) = – x2

+ 150x – 2600. (2)

(b) The maximum profit occurs at the vertex of the function P(x). How many machines should be

made and sold each month for a maximum profit? (2)

(c) If the company does maximize profit, what is the selling price of each machine? (4)

(d) Given that P (x) = (x – 20) (130 – x), find the smallest number of machines the company must

make and sell each month in order to make positive profit. (4)

(Total 12 marks)