Date | November 2021 | Marks available | 1 | Reference code | 21N.2.SL.TZ0.8 |
Level | Standard Level | Paper | Paper 2 | Time zone | Time zone 0 |
Command term | Show that | Question number | 8 | Adapted from | N/A |
Question
The height of water, in metres, in Dungeness harbour is modelled by the function , where is the number of hours after midnight, and and are constants, where and .
The following graph shows the height of the water for hours, starting at midnight.
The first high tide occurs at and the next high tide occurs hours later. Throughout the day, the height of the water fluctuates between and .
All heights are given correct to one decimal place.
Show that .
Find the value of .
Find the value of .
Find the smallest possible value of .
Find the height of the water at .
Determine the number of hours, over a 24-hour period, for which the tide is higher than metres.
Markscheme
OR A1
AG
[1 mark]
OR (M1)
A1
[2 marks]
OR (M1)
A1
[2 marks]
METHOD 1
substituting and for example into their equation for (A1)
attempt to solve their equation (M1)
A1
METHOD 2
using horizontal translation of (M1)
(A1)
A1
METHOD 3
(A1)
attempts to solve their for (M1)
A1
[3 marks]
attempt to find when or , graphically or algebraically (M1)
A1
[2 marks]
attempt to solve (M1)
times are and (A1)
total time is
(hours) A1
Note: Accept .
[3 marks]