<PRE><B>Question 1029598</B>
d(t) = 4.5 + 1.5 sin pi t/12 
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5 = 4.5 + (1.5 * sin(pi * t/12))
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0.5 = 1.5 * sin(pi * t/12)
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note that pi = 180 degrees
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1/3 = sin(15t)
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determine angle from inverse sin function = 1/3
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15t = 19.471220634
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t = 1.298081376 approx 1.3 hours
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we need 9 hours to unload the ship
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d(10.3) = 4.5 + (1.5 * sin(pi * (10.3)/12)) =
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4.5 + (1.5 * 0.430511097) = 5.145766646 meters
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*****yes, the ship will be able to exit 9 hours later
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the sin curve is periodic, here is a graph of the equation
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{{{ graph(300, 200, -20, 20, -1, 7, 4.5 + 1.5*sin(pi*(x/12))) }}} 
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we want to know the value of t when the sin(15t) = 1/3 again *****
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note we subtract 19.471220634 from 180 = 160.528779366
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15t = 160.528779366
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t = 10.701918624 
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***The ship has an addition 24 minutes before it can not sale out of the harbor
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