The height above the ground of one of the seats of a Ferris wheel, in metres, can be modelled by the function
 = 8 + 7(sin15(t)))
where

is measured in seconds.
a) What is the maximum and minimum height reached by any seat?
My answer:
Sub in t = 90 and t = 270 to obtain the max and the min, 15m and 1m.
Mr F says: Correct. But easier to just say that the min and max value of sin is +1 and -1 .....
b) How long does it take for the seat on this ride to rotate back to its starting point?
How exactly am I supposed to figure this out? I know I'm supposed to isolate for

, but I can only do that if I have a value for
)
.
Any help would be appreciated.