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Date May 2022 Marks available 2 Reference code 22M.1.SL.TZ1.2
Level Standard Level Paper Paper 1 Time zone Time zone 1
Command term Find Question number 2 Adapted from N/A

Question

A vertical pole stands on horizontal ground. The bottom of the pole is taken as the origin, O, of a coordinate system in which the top, F, of the pole has coordinates (0, 0, 5.8). All units are in metres.


The pole is held in place by ropes attached at F.

One of the ropes is attached to the ground at a point A with coordinates (3.2, 4.5, 0). The rope forms a straight line from A to F.

Find the length of the rope connecting A to F.

[2]
a.

Find FÂO, the angle the rope makes with the ground.

[2]
b.

Markscheme

3.22+4.52+5.82           (M1)

=8.01   8.00812 m          A1

 

[2 marks]

a.

FÂO=sin-15.88.00812  OR  cos-15.521778.00812  OR  tan-15.85.52177           (M1)

46.4°   46.4077°          A1

 

[2 marks]

b.

Examiners report

This question was the first of its type to be tested and the problem was reduced (erroneously) to 2D trigonometry. Whilst a minority of candidates did tackle this part correctly, many simply arrived at an incorrect length with (5.8)2+(4.5)2=7.34 metres.

a.

The incorrect interpretation of the diagram as being 2D, meant that there was an assumption that OA was of length 3.2 metres and so tan-15.83.2=61.1° was seen on many scripts. If, using their incorrect answer for part (a), the candidate had used sin-15.8their part (a) it was possible to award “follow through” marks.

b.

Syllabus sections

Topic 3—Geometry and trigonometry » SL 3.1—3d space, volume, angles, midpoints
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Topic 3—Geometry and trigonometry » SL 3.2—2d and 3d trig
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Topic 3—Geometry and trigonometry

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