Applications of periodic functions : tides and times
On a typical day at a seaport, the water has a maximum depth of 16 m at 7:00 AM. The minimum depth of 4m occurs at 1:24 PM. Assume that the relation between depth h, in metres, and the time t, in hours, is a sinusoidal function.
a) write an equation for h for any time, t hours.
My answer: (in radians)
b) Give the depth h at 10:30 QM (accurate to two decimals)
My Answer: 10:30 = 10.5 hours, I punched my equation into my TI-83 Plus and I got 9.12 as the value
c) find two times before noon when h is 14m (accurately to the nearest minute)
Here's my problem; I punched in a second equation and then found the intersects, but I that gives me decimals which are not as simple to convert from hundredths of hours to minutes. How can I make the conversion easily? and am I going about this question correctly?