not a, shallow = -2+5 = 3
check b, 2 sin (.51*12 -.4) + 5 = 2 sin (around 2 pi) +5 around 5, no
t is HOURS </= 15, not days] so not c
YES d, because 2+5 = 7
e. when t = 0 D = 2 sin (-.4 ) + 5 = - 2(.4)+5 = 5-.8 =4.2 YES
f. .51*12 = which is close but not exactly 2 pi. In fact nothing but 2 pi is exactly 2 pi
g. well, it goes up and down
May someone help me with this HW problem?
The depth (D metres) of water in a harbour at a time (t hours) after midnight on a particular day can be modelled by the function
D = 2 sin(0.51t - 0.4) +5, t <=15,
where radians have been used.
Select the two options which are correct statements about the predictions based on this model.
Select one or more:
a) The smallest depth is 5 metres.
b) At midday, the depth is approximately 7 metres.
c) The model can be used to predict the tide for up to 15 days.
d) The largest depth is 7 metres.
e) At midnight the depth is approximately 4.2 metres.
f) The time between the two high tides is exactly 12 hours.
g) The depth of water in the harbour falls after midnight.
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