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Date May Example question Marks available 5 Reference code EXM.2.AHL.TZ0.13
Level Additional Higher Level Paper Paper 2 Time zone Time zone 0
Command term Find Question number 13 Adapted from N/A

Question

Beth goes for a run. She uses a fitness app to record her distance, ss km, and time, tt minutes. A graph of her distance against time is shown.

Beth runs at a constant speed of 2.3 ms–1 for the first 8 minutes.

Between 8 and 20 minutes, her distance can be modeled by a cubic function, s=at3+bt2+ct+ds=at3+bt2+ct+d. She reads the following data from her app.

Hence find

Calculate her distance after 8 minutes. Give your answer in km, correct to 3 decimal places.

[2]
a.

Find the value of aabbcc and dd.

[5]
b.

the distance she runs in 20 minutes.

[2]
c.i.

her maximum speed, in ms–1.

[4]
c.ii.

Markscheme

2.3×8×601000=1.1042.3×8×601000=1.104    M1A1

[2 marks]

a.

either using a cubic regression or solving a system of 4 equations         M1

a=0.00364,b=0.150,c=1.67,d=6.72a=0.00364,b=0.150,c=1.67,d=6.72         A1A1A1A1

[5 marks]

b.

s(20)=4.21s(20)=4.21 km  (Note: Condone s(20)=4.2s(20)=4.2 km obtained from using rounded values.)      M1A1

[2 marks]

c.i.

EITHER finding maximum of dsdtdsdt OR solving d2sdt2=0d2sdt2=0     M1

maximum speed = 0.390… km per minute      A1

maximum speed = 6.51 ms–1     M1A1

[4 marks]

c.ii.

Examiners report

[N/A]
a.
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b.
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c.i.
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c.ii.

Syllabus sections

Topic 2—Functions » AHL 2.9—HL modelling functions
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Topic 2—Functions

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