Assignment Log and Expo
Assignment Log and Expo
Assignment Log and Expo
(b) The graph of g is a transformation of the graph of f. Give a full geometric description of
this transformation.
(3)
(Total 7 marks)
x
2. Let f(x) = log3 + log3 16 – log3 4, for x > 0.
2
ln ax
The function f can also be written in the form f(x) = .
ln b
IB Questionbank Maths SL 1
The point A lies on the graph of f. At A, x = 4.5.
(e) On your diagram, sketch the graph of f–1, noting clearly the image of point A.
(4)
(Total 16 marks)
(b) Given that f(15) = 3.49 (correct to 3 significant figures), find the value of k.
(3)
(iii) Write down the equation of the horizontal asymptote of the graph f.
(5)
IB Questionbank Maths SL 2
Let g(x) = –x2 + 12x – 24.
(c) After k minutes, the rate of increase in n is greater than 10 000 bacteria per minute. Find
the least value of k, where k .
(4)
(Total 8 marks)
IB Questionbank Maths SL 3
5. A city is concerned about pollution, and decides to look at the number of people using taxis. At
the end of the year 2000, there were 280 taxis in the city. After n years the number of taxis, T, in
the city is given by
T = 280 1.12n.
(a) (i) Find the number of taxis in the city at the end of 2005.
(ii) Find the year in which the number of taxis is double the number of taxis there were
at the end of 2000.
(6)
(b) At the end of 2000 there were 25 600 people in the city who used taxis. After n years the
number of people, P, in the city who used taxis is given by
2 560 000
P= .
10 90e – 0.1n
(i) Find the value of P at the end of 2005, giving your answer to the nearest whole
number.
(ii) After seven complete years, will the value of P be double its value at the end of
2000? Justify your answer.
(6)
(c) Let R be the ratio of the number of people using taxis in the city to the number of taxis.
The city will reduce the number of taxis if R 70.
(ii) After how many complete years will the city first reduce the number of taxis?
(5)
(Total 17 marks)
(a) logx 49 = 2
(3)
(b) log2 8 = x
(2)
IB Questionbank Maths SL 4
1
(c) log25 x =
2
(3)
7. The functions f (x) and g (x) are defined by f (x) = ex and g (x) = ln (1+ 2x).
8. The population of a city at the end of 1972 was 250 000. The population increases by 1.3 per
year.
(c) Find the coordinates of the point of intersection of the graphs of f and g.
(Total 6 marks)
IB Questionbank Maths SL 5
(a) Write down the value of
(i) f (a);
(ii) f (1);
(iii) f (a4 ).
(3)
1
f
–2 –1 0 1 2 x
–1
–2
IB Questionbank Maths SL 6
11. The area A km2 affected by a forest fire at time t hours is given by A = A0 ekt.
When t = 5, the area affected is 1 km2 and the rate of change of the area is 0.2 km2 h−1.
1
(b) Given that A0 = , find the value of t when 100 km2 are affected.
e
(2)
(Total 6 marks)
(a) ln (x + 2) = 3.
14. There were 1420 doctors working in a city on 1 January 1994. After n years the number of
doctors, D, working in the city is given by
D = 1420 + 100n.
(a) (i) How many doctors were there working in the city at the start of 2004?
(ii) In what year were there first more than 2000 doctors working in the city?
(3)
IB Questionbank Maths SL 7
At the beginning of 1994 the city had a population of 1.2 million. After n years, the population,
P, of the city is given by
(ii) Calculate the percentage growth in population between 1 January 1994 and 1
January 2004.
(iii) In what year will the population first become greater than 2 million?
(7)
(c) (i) What was the average number of people per doctor at the beginning of 1994?
(ii) After how many complete years will the number of people per doctor first fall
below 600?
(5)
(Total 15 marks)
IB Questionbank Maths SL 8
15. The population p of bacteria at time t is given by p = 100e0.05t.
Calculate
Working:
Answers:
(a) …………………………………………..
(b) …………………………………………..
(Total 6 marks)
IB Questionbank Maths SL 9
16. The mass m kg of a radio-active substance at time t hours is given by
m = 4e–0.2t.
(b) The mass is reduced to 1.5 kg. How long does this take?
Working:
Answers:
(a) ..................................................................
(b) ..................................................................
(Total 6 marks)
IB Questionbank Maths SL 10
17. $1000 is invested at 15% per annum interest, compounded monthly. Calculate the minimum
number of months required for the value of the investment to exceed $3000.
Working:
Answer:
......................................................................
(Total 6 marks)
18. Each year for the past five years the population of a certain country has increased at a steady
rate of 2.7% per annum. The present population is 15.2 million.
Working:
Answers:
(a) ..................................................................
(b) ..................................................................
(Total 4 marks)
19. Michele invested 1500 francs at an annual rate of interest of 5.25 percent,
compounded annually.
IB Questionbank Maths SL 11
(a) Find the value of Michele’s investment after 3 years. Give your answer to the nearest
franc.
(3)
(b) How many complete years will it take for Michele’s initial investment to double in value?
(3)
(c) What should the interest rate be if Michele’s initial investment were to double in value in
10 years?
(4)
(Total 10 marks)
20. A group of ten leopards is introduced into a game park. After t years the number of leopards, N,
is modelled by N = 10 e0.4t.
(b) How long will it take for the number of leopards to reach 100? Give your answers to an
appropriate degree of accuracy.
Working:
Answers:
(a) ..................................................................
(b) ..................................................................
(Total 4 marks)
IB Questionbank Maths SL 12
21. The diagram shows three graphs.
B
y
A
Write down
Working:
Answers:
(a) ..................................................................
(b) ..................................................................
(Total 4 marks)
22. Initially a tank contains 10 000 litres of liquid. At the time t = 0 minutes a tap is opened, and
liquid then flows out of the tank. The volume of liquid, V litres, which remains in the tank after t
minutes is given by
IB Questionbank Maths SL 13
V = 10 000 (0.933t).
(b) Find how long, to the nearest second, it takes for half of the initial amount of liquid to
flow out of the tank.
(3)
(c) The tank is regarded as effectively empty when 95% of the liquid has flowed out.
Show that it takes almost three-quarters of an hour for this to happen.
(3)
(ii) Hence or otherwise, estimate the initial flow rate of the liquid.
Give your answer in litres per minute, correct to two significant figures.
(3)
(Total 10 marks)
23. A population of bacteria is growing at the rate of 2.3% per minute. How long will it take for the
size of the population to double? Give your answer to the nearest minute.
Working:
Answer:
......................................................................
(Total 4 marks)
IB Questionbank Maths SL 14