Date | May 2021 | Marks available | 1 | Reference code | 21M.1.SL.TZ1.5 |
Level | Standard Level | Paper | Paper 1 | Time zone | Time zone 1 |
Command term | Explain | Question number | 5 | Adapted from | N/A |
Question
The Voronoi diagram below shows three identical cellular phone towers, and . A fourth identical cellular phone tower, is located in the shaded region. The dashed lines in the diagram below represent the edges in the Voronoi diagram.
Horizontal scale: unit represents .
Vertical scale: unit represents .
Tim stands inside the shaded region.
Tower has coordinates and the edge connecting vertices and has equation .
Explain why Tim will receive the strongest signal from tower .
Write down the coordinates of tower .
Tower has coordinates .
Find the gradient of the edge of the Voronoi diagram between towers and .
Markscheme
every point in the shaded region is closer to tower R1
Note: Specific reference must be made to the closeness of tower .
[1 mark]
A1A1
Note: Award A1 for each correct coordinate. Award at most A0A1 if parentheses are missing.
[2 marks]
correct use of gradient formula (M1)
e.g.
taking negative reciprocal of their (at any point) (M1)
edge gradient A1
[3 marks]