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Date	May 2019	Marks available	2	Reference code	19M.2.SL.TZ1.T_4
Level	Standard Level	Paper	Paper 2	Time zone	Time zone 1
Command term	Justify and State	Question number	T_4	Adapted from	N/A

Question

Consider the function $f\left( x \right) = {x^3} - 5{x^2} + 6x - 3 + \frac{1}{x}$ , $x > 0$

The function $f\left( x \right) = {x^3} - 5{x^2} + 6x - 3 + \frac{1}{x}$ , $x > 0$ , models the path of a river, as shown on the following map, where both axes represent distance and are measured in kilometres. On the same map, the location of a highway is defined by the function $g\left( x \right) = 0.5{\left( 3 \right)^{ - x}} + 1$ .

The origin, O(0, 0) , is the location of the centre of a town called Orangeton.

A straight footpath, $P$ , is built to connect the centre of Orangeton to the river at the point where $x = \frac{1}{2}$ .

Bridges are located where the highway crosses the river.

A straight road is built from the centre of Orangeton, due north, to connect the town to the highway.

State the domain of $P$ .

[2]

b.ii.

Find the distance from the centre of Orangeton to the point at which the road meets the highway.

[2]

d.

This straight road crosses the highway and then carries on due north.

State whether the straight road will ever cross the river. Justify your answer.

[2]

e.

Markscheme

0 < $x$ < $\frac{1}{2}$ (A1)(A1)

Note: Award (A1) for both endpoints correct, (A1) for correct mathematical notation indicating an interval with two endpoints. Accept weak inequalities. Award at most (A1)(A0) for incorrect notation such as 0 − 0.5 or a written description of the domain with correct endpoints. Award at most (A1)(A0) for 0 < $y$ < $\frac{1}{2}$ .

[2 marks]

b.ii.

$g\left( 0 \right) = 0.5{\left( 3 \right)^0} + 1$ (M1)

1.5 (km) (A1)(G2)

[2 marks]

d.

domain given as $x > 0$ (but equation of road is $x = 0$ ) (R1)

OR

(equation of road is $x = 0$ ) the function of the river is asymptotic to $x = 0$ (R1)

so it does not meet the river (A1)

Note: Award the (R1) for a correct mathematical statement about the equation of the river (and the equation of the road). Justification must be based on mathematical reasoning. Do not award (R0)(A1).

[2 marks]

e.

Examiners report

[N/A]

b.ii.

[N/A]

d.

[N/A]

e.

Syllabus sections

Topic 2—Functions » SL 2.2—Functions, notation domain, range and inverse as reflection

Show 123 related questions

18M.1.AHL.TZ1.H_9c:
Sketch the graph of $y = f\left( x \right)$ showing clearly the position of the points A and B.
22M.2.SL.TZ2.4c.ii:
an appropriate range for $h (t)$ .
22M.2.SL.TZ2.4c.i:
an appropriate domain for $h (t)$ .
18M.2.AHL.TZ2.H_10c:
Sketch the graph of $y = g\left( t \right)$ for t ≤ 0. Give the coordinates of any intercepts and the equations of any asymptotes.
19M.2.AHL.TZ2.H_4a:
Sketch the graphs $y = {\text{si}}{{\text{n}}^3}\,x + {\text{ln}}\,x$ and $y = 1 + {\text{cos}}\,x$ on the following axes for 0 < $x$ ≤ 9.
17M.1.AHL.TZ1.H_6a:
Sketch the graphs on the same set of axes.
18M.2.SL.TZ1.T_4e:
Sketch the graph of y = f (x) for 0 < x ≤ 6 and −30 ≤ y ≤ 60.
Clearly indicate the minimum point P and the x-intercepts on your graph.
17N.2.AHL.TZ0.H_10d:
This region is now rotated through $2\pi$ radians about the $x$ -axis. Find the volume of revolution.
18M.1.AHL.TZ2.H_10b.ii:
Sketch the graph of $y = g\left( x \right)$ . State the equations of any asymptotes and the coordinates of any intercepts with the axes.
18M.2.AHL.TZ2.H_10d.ii:
Show that $\alpha$ + β < −2.
17M.1.SL.TZ2.T_14b:
Use your graphic display calculator to find how long it will take for Jashanti to have saved enough money to buy the car.
22M.1.AHL.TZ2.10b:
Solve $f (x) = f^{- 1} (x)$ .
EXN.2.SL.TZ0.3b.ii:
Hence write down the domain of $h$ .
22M.1.SL.TZ1.11c:
Given $0 < M < 8$ , find the range for $N$ .
22M.1.SL.TZ1.3c:
State an appropriate domain for $t$ in this model.
21N.1.SL.TZ0.5a:
Find the range of $h$ .
18M.1.AHL.TZ2.H_2a:
Sketch the graphs of $y = \frac{x}{2} + 1$ and $y = \left| {x - 2} \right|$ on the following axes.
18N.1.AHL.TZ0.H_3b:
Write down the least value of $a$ such that $g$ has an inverse.
18N.1.AHL.TZ0.H_3a:
For $a = - \frac{\pi }{2}$ , sketch the graph of $y = g\left( x \right)$ . Indicate clearly the maximum and minimum values of the function.
17M.1.AHL.TZ1.H_6b:
Given that the graphs enclose a region of area 18 square units, find the value of b.
19M.2.SL.TZ1.S_9b:
Find u.
19M.2.SL.TZ2.T_5f:
Find the equation of the tangent line to the graph of $y = f\left( x \right)$ at $x = 2$ . Give the equation in the form $ax + by + d = 0$ where, $a$ , $b$ , and $d \in \mathbb{Z}$ .
18M.2.SL.TZ1.T_4a:
Find the value of k.
17M.1.SL.TZ2.T_14a:
Write down the amount of money Jashanti saves per month.
18N.1.AHL.TZ0.H_3c.i:
For the value of $a$ found in part (b), write down the domain of ${g^{ - 1}}$ .
19M.2.SL.TZ1.T_4b.ii:
State the domain of $P$ .
18M.2.SL.TZ2.T_6f:
Given that y = 2x³ − 9x² + 12x + 2 = k has three solutions, find the possible values of k.
17N.1.SL.TZ0.S_5a:
Find $(g \circ f)(x)$ .
19M.2.SL.TZ1.S_9d.iii:
Hence or otherwise, find the obtuse angle formed by the tangent line to $f$ at $x = 8$ and the tangent line to $f$ at $x = 2$ .
18M.2.SL.TZ2.T_6a:
Sketch the curve for −1 < x < 3 and −2 < y < 12.
19M.1.AHL.TZ1.H_8d:
Sketch the curve $y = f\left( x \right)$ , 0 ≤ $x$ ≤ 5 indicating clearly the coordinates of the maximum and minimum points and any intercepts with the coordinate axes.
18M.2.AHL.TZ2.H_10a.ii:
With reference to your graph, explain why $f$ is a function on the given domain.
17M.2.AHL.TZ1.H_12e:
Find the inverse function ${g^{ - 1}}$ and state its domain.
17M.1.AHL.TZ2.H_2c:
Write down the domain and range of ${f^{ - 1}}$ .
16N.2.SL.TZ0.S_1b:
Find $(g \circ f)(x)$ .
17M.1.AHL.TZ1.H_11a.ii:
Factorize ${x^2} + 3x + 2$ .
18M.2.AHL.TZ2.H_10a.i:
Sketch the graph of $y = f\left( x \right)$ for $- \frac{{5\pi }}{8} \leqslant x \leqslant \frac{\pi }{8}$ .
18M.2.SL.TZ2.T_6b:
A teacher asks her students to make some observations about the curve.

Three students responded.
Nadia said “The x-intercept of the curve is between −1 and zero”.
Rick said “The curve is decreasing when x < 1 ”.
Paula said “The gradient of the curve is less than zero between x = 1 and x = 2 ”.

State the name of the student who made an incorrect observation.
19M.2.SL.TZ1.S_9d.i:
Find $\left( {f \circ f} \right)\left( x \right)$ .
18N.1.AHL.TZ0.H_3c.ii:
For the value of $a$ found in part (b), find an expression for ${g^{ - 1}}\left( x \right)$ .
18M.2.SL.TZ1.T_4b:
Using your value of k , find f ′(x).
18M.1.AHL.TZ2.H_10b.i:
Express $g\left( x \right)$ in the form $A + \frac{B}{{x - 2}}$ where A, B are constants.
18M.2.AHL.TZ2.H_10a.iii:
Explain why $f$ has no inverse on the given domain.
19M.2.SL.TZ1.S_9c:
Find the acute angle between $y = x$ and $L$ .
17M.1.AHL.TZ1.H_11e:
Sketch the graph of $y = f\left( {\left| x \right|} \right)$ .
17M.2.AHL.TZ1.H_12c:
Explain why $f$ is an even function.
17M.1.AHL.TZ2.H_2a:
Write down the range of $f$ .
16N.1.AHL.TZ0.H_3b:
find the value of $b$ .
18M.1.SL.TZ1.S_3c:
On the grid above, sketch the graph of f ⁻¹.
16N.2.AHL.TZ0.H_5b:
State the range of $f$ .
16N.1.SL.TZ0.T_9b:
Find the value of $b$ .
17M.2.SL.TZ2.S_6b:
On the following grid, sketch the graph of $(f \circ g)(x)$ , for $0 \leqslant x \leqslant 2.25$ .
17M.1.AHL.TZ2.H_2b:
Find an expression for ${f^{ - 1}}(x)$ .
17M.1.AHL.TZ1.H_11d:
Hence find the value of $p$ if $\int_0^1 {f(x){\text{d}}x = \ln (p)}$ .
17N.2.AHL.TZ0.H_10a.i:
Show that the $x$ -coordinate of the minimum point on the curve $y = f(x)$ satisfies the equation $\tan x = 2x$ .
19M.1.AHL.TZ1.H_8a:
Write down the $x$ -coordinate of the point of inflexion on the graph of $y = f\left( x \right)$ .
17M.1.SL.TZ2.T_14c:
Calculate how much extra money Jashanti needs.
17M.2.AHL.TZ1.H_12g.ii:
Hence, show that there are no solutions to $({g^{ - 1}})'(x) = 0$ .
18M.1.AHL.TZ2.H_10c:
The function $h$ is defined by $h\left( x \right) = \sqrt x$ , for $x$ ≥ 0.

State the domain and range of $h \circ g$ .
17N.1.AHL.TZ0.H_6a:
Sketch the graph of $y = \frac{{1 - 3x}}{{x - 2}}$ , showing clearly any asymptotes and stating the coordinates of any points of intersection with the axes.
18M.1.AHL.TZ1.H_9b.i:
Show that there is exactly one point of inflexion, B, on the graph of $y = f\left( x \right)$ .
18M.1.AHL.TZ2.H_2b:
Solve the equation $\frac{x}{2} + 1 = \left| {x - 2} \right|$ .
18M.1.AHL.TZ1.H_9a:
The graph of $y = f\left( x \right)$ has a local maximum at A. Find the coordinates of A.
17M.1.AHL.TZ1.H_11a.i:
Express ${x^2} + 3x + 2$ in the form ${(x + h)^2} + k$ .
16N.1.AHL.TZ0.H_3a:
state the value of $a$ and the value of $c$ ;
17N.2.AHL.TZ0.H_10c:
Find the coordinates of the point on the graph of $f$ where the normal to the graph is parallel to the line $y = - x$ .
17N.2.AHL.TZ0.H_10b:
Sketch the graph of $y = f(x)$ showing clearly the minimum point and any asymptotic behaviour.
20N.1.SL.TZ0.T_2a.i:
State, in the context of the question, what the value of $34.50$ represents.
20N.1.SL.TZ0.T_2a.ii:
State, in the context of the question, what the value of $8.50$ represents.
20N.1.SL.TZ0.T_2c:
Kaelani has $450 PGK$ .

Find the maximum number of large cheese pizzas that Kaelani can order from Olava’s Pizza Company.
17N.2.AHL.TZ0.H_10a.ii:
Determine the values of $x$ for which $f(x)$ is a decreasing function.
17M.1.AHL.TZ1.H_11c:
Show that $\frac{1}{{x + 1}} - \frac{1}{{x + 2}} = \frac{1}{{{x^2} + 3x + 2}}$ .
20N.1.SL.TZ0.T_2b:
Write down the minimum number of pizzas that can be ordered.
17M.1.SL.TZ1.T_12a:
Write down the domain of the function.
16N.2.AHL.TZ0.H_5c:
Solve the inequality $\left| {3x\arccos (x)} \right| > 1$ .
17M.2.AHL.TZ1.H_12f:
Find $g'(x)$ .
16N.2.SL.TZ0.S_1a:
Find $f(8)$ .
17M.2.SL.TZ2.S_6c:
The equation $(f \circ g)(x) = k$ has exactly two solutions, for $0 \leqslant x \leqslant 2.25$ . Find the possible values of $k$ .
EXN.2.SL.TZ0.3c:
Find the range of $h$ .
18M.2.SL.TZ2.T_6d:
Find $\frac{{{\text{dy}}}}{{{\text{dx}}}}$ .
18M.1.AHL.TZ1.H_9b.ii:
The coordinates of B can be expressed in the form B $\left( {{2^a},\,b \times {2^{ - 3a}}} \right)$ where a, b $\in \mathbb{Q}$ . Find the value of a and the value of b.
17M.2.AHL.TZ1.H_12d:
Explain why the inverse function ${f^{ - 1}}$ does not exist.
17M.2.AHL.TZ1.H_12g.i:
Hence, show that there are no solutions to $g'(x) = 0$ ;
17N.1.AHL.TZ0.H_6b:
Hence or otherwise, solve the inequality $\left| {\frac{{1 - 3x}}{{x - 2}}} \right| < 2$ .
21M.1.SL.TZ1.4a:
Find the total cost of buying $40$ litres of gas at Leon’s gas station.
18M.2.SL.TZ1.T_4c:
Use your answer to part (b) to show that the minimum value of f(x) is −22 .
21M.1.SL.TZ1.4b:
Find $L^{- 1} (70)$ .
18M.2.AHL.TZ2.H_10d.i:
Find $\alpha$ and β in terms of $k$ .
19M.2.SL.TZ2.T_5d:
Find $f'\left( x \right)$ .
17M.1.SL.TZ1.T_12b.i:
Draw the line $y = - 6$ on the axes.
19M.2.SL.TZ1.T_4d:
Find the distance from the centre of Orangeton to the point at which the road meets the highway.
19M.1.AHL.TZ1.H_8b:
find the value of $f\left( 1 \right)$ .
19N.1.SL.TZ0.T_10b:
While in Kota Kinabalu, Criselda spent $440 MYR$ . She returned to the Currency Exchange counter and changed the remainder of her $MYR$ into $USD$ .

Calculate the amount of $USD$ she received.
17M.2.SL.TZ2.S_6a:
Show that $(f \circ g)(x) = {x^4} - 4{x^2} + 3$ .
19M.2.AHL.TZ2.H_4b:
Hence solve ${\text{si}}{{\text{n}}^3}\,x + {\text{ln}}\,x - {\text{cos}}\,x - 1 < 0$ in the range 0 < $x$ ≤ 9.
17N.1.SL.TZ0.S_5b:
Given that $\mathop {\lim }\limits_{x \to + \infty } (g \circ f)(x) = - 3$ , find the value of $b$ .
16N.2.SL.TZ0.S_1c:
Solve $(g \circ f)(x) = 0$ .
18M.1.AHL.TZ2.H_10a:
Find the inverse function ${f^{ - 1}}$ , stating its domain.
19M.2.SL.TZ1.S_9a:
Find the gradient of $L$ .
19N.1.SL.TZ0.T_10a:
Calculate the amount of $MYR$ that Criselda received.
19M.2.SL.TZ1.S_9d.ii:
Hence, write down ${f^{ - 1}}\left( x \right)$ .
18M.2.AHL.TZ2.H_10a.iv:
Explain why $f$ is not a function for $- \frac{{3\pi }}{4} \leqslant x \leqslant \frac{\pi }{4}$ .
16N.2.AHL.TZ0.H_5a:
Sketch the graph of $f$ indicating clearly any intercepts with the axes and the coordinates of any local maximum or minimum points.
17M.1.SL.TZ1.T_12c:
Find the range of values of $k$ for which $f(x) = k$ has no solution.
17M.2.AHL.TZ1.H_12b:
Sketch the graph of $y = f(x)$ showing clearly the equations of asymptotes and the coordinates of any intercepts with the axes.
17M.1.SL.TZ1.T_12b.ii:
Write down the number of solutions to $f(x) = - 6$ .
21M.1.SL.TZ2.7b:
Find the value of $f^{- 1} (0)$ .
21M.1.SL.TZ2.7a:
Find the range of $f$ .
21M.1.AHL.TZ2.2c:
Write down the range of $f^{- 1} (x)$ .
17M.2.SL.TZ2.S_3a:
Write down the range of $f$ .
17M.2.AHL.TZ1.H_12a:
Find the largest possible domain $D$ for $f$ to be a function.
19M.1.AHL.TZ1.H_8c:
find the value of $f\left( 4 \right)$ .
21M.1.AHL.TZ2.2b:
Find an expression for the inverse function $f^{- 1} (x)$ . The domain is not required.
21M.1.AHL.TZ2.2a:
Find the range of $f$ .
18M.2.AHL.TZ2.H_10b:
Show that $g\left( t \right) = {\left( {\frac{{1 + t}}{{1 - t}}} \right)^2}$ .
17M.1.AHL.TZ1.H_11f:
Determine the area of the region enclosed between the graph of $y = f\left( {\left| x \right|} \right)$ , the $x$ -axis and the lines with equations $x = - 1$ and $x = 1$ .
17M.1.AHL.TZ1.H_11b:
Sketch the graph of $f(x)$ , indicating on it the equations of the asymptotes, the coordinates of the $y$ -intercept and the local maximum.
19M.2.SL.TZ2.T_5e:
Find the gradient of the graph of $y = f\left( x \right)$ at $x = 2$ .
EXN.2.SL.TZ0.3b.i:
Find the value of $t$ at which the ball hits the ground.
EXN.2.SL.TZ0.3a:
Find an expression for the height $h$ of the ball at time $t$ .
21N.1.SL.TZ0.5b.i:
Find $h^{- 1} (10)$ .
21N.1.SL.TZ0.5b.ii:
In the context of the question, interpret your answer to part (b)(i).
21N.1.SL.TZ0.5b.iii:
Write down the range of $h^{- 1}$ .

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