IB Maths AI HL Topic 2: Functions questions

Exam-style questions in the shape of Paper 1 and Paper 2, with full markschemes. Read the markscheme, or type, photograph or draw your answer and get it marked.

Question 1

Paper 1Easy5 marks

A positioning device converts a control setting xx to an output f(x)f(x) Figure 1 shows its calibration curve. The rule is

f(x)=(x−3)2−2f(x)=(x-3)^2-2

on the branch shown. Both xx and f(x)f(x) are measured in device units.

01234567-202468101214x (device units)f(x) (device units)
(a)

Use Figure 1 to write down the range of ff

[1]
(b)

Find f−1(x)f^{-1}(x)

[1]
(c)

State the domain of f−1f^{-1}

[1]
(d)

Complete each statement, including the appropriate domain for xx

(i)

(f∘f−1)(x)=…(f\circ f^{-1})(x)=\dots

[1]
(ii)

(f−1∘f)(x)=…(f^{-1}\circ f)(x)=\dots

[1]

Question 2

Paper 1Easy5 marks

A local market sells honey in jars. Let qq be the quantity, in thousands of jars per week, and let pp be the price, in dollars per jar. Figure 1 shows the demand and supply models for this market.

0102030405060700102030405060708090q (thousands of jars per week)p (dollars per jar)Demand: pD = 78 - 1.2qSupply: pS = 12 + 0.8q
(a)

Write down the quantity at which the demand curve intersects the quantity axis.

[1]
(b)

Using graphing technology, find the market equilibrium. Give the quantity and price, with their units.

[3]
(c)

Write down the price at which the supply curve intersects the price axis.

[1]

Question 3

Paper 1Medium6 marks

During an 8-hour monitoring period, the water depths in two tanks are modelled by

f(t)=−0.25(t−4)2+10,g(t)=t+2,f(t)=-0.25(t-4)^2+10,\qquad g(t)=t+2,

where f(t)f(t) is the depth in Tank A, g(t)g(t) is the depth in Tank B, and tt is the time in hours since monitoring began. Depths are in centimetres, and 0≤t≤80\leq t\leq 8

(a)

Construct a function D(t)D(t) such that D(t)>0D(t)>0 means Tank A is deeper than Tank B. Give D(t)D(t) in expanded form.

[2]
(b)

Use a GDC to graph y=D(t)y=D(t) then sketch the graph for 0≤t≤80\leq t\leq 8 in your answer booklet. Label both axes with units and indicate the yy-intercept, turning point, tt-intercept and value at t=8t=8

[3]
(c)

Use your sketch to state which tank has the greater depth at t=7t=7

[1]

Question 4

Paper 1Easy5 marks

A technician records the volume of water in a reservoir during a filling test.

Time, tt (min)051015
Volume, VV (L)18314356

The technician proposes a linear model V=mt+cV=mt+c

(a)

State one feature of the measurements that supports the use of a linear model.

[1]
(b)

Using the measurements at t=0t=0 and t=15t=15 show that the fitted model is

V=18+3815t.V=18+\frac{38}{15}t.
[2]
(c)

Hence estimate the volume of water after 12 minutes.

[1]
(d)

State whether using the model to predict the volume after 24 minutes is interpolation or extrapolation.

[1]

Question 5

Paper 1Medium7 marks

A website records the number of visits per day during the first five days after its launch.

tt number of days after launch12345
VV visits per day320 000470 000760 0001 040 0001 700 000

To work with more manageable values, let W=V/100 000W=V/100\,000 The manager considers an exponential model W=Abt−1W=A b^{t-1} and a power model W=CtpW=Ct^p

(a)

For the exponential model, determine the fitted values of AA and bb and the Pearson’s product moment correlation coefficient for the linearized data. Give your answers to three significant figures.

[3]
(b)

For the power model, determine the fitted values of CC and pp and the Pearson’s product moment correlation coefficient for the linearized data. Give your answers to three significant figures.

[3]
(c)

State which model is better supported by these data, giving a reason based on the correlation coefficients.

[1]

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