Section B ( 40 marks )
7 . In a coast , the height of the sea water in metres is modelled by the function h( t) � psin ( qt)
� r , where t is the number of hours after 12 am on 3 January
2021 , for 0 �t
� 48 .
The point A ( 2.75,1.9 ) represents the first low tide and B ( 13.75,1.9 ) represents the next low tide . It is given that the difference in height between low tide and high tide is 4.3 m .
( a ) Find the height of a high tide .
( b ) Show that p �� 2.15 .
( c ) Find the value of
[ 2 ]
[ 2 ]
( i ) q ;
( ii ) r .
( d ) There are three low tides on 4 January 2021 . At what time does the third low tide occur ?
[ 5 ]
[ 3 ]
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