A series of locks manages the water height along a water source used to produce energy. As the locks are opened and closed, the water height between two consecutive locks fluctuates. The height of the water at point B located between two locks is observed. Water height measurements are made every 10 minutes beginning at 8:00 a.m
Amplitude is 13 so the wave goes from 13 to -13 AND it is shifted UP by 24
so max height will be 13 + 24 = 37ft min height will be -13 + 24 = 11 ft
Min height will be when the cos fxn = 1
when cos (............) = -1 (0 degrees)
pi x /60 - 5pi/12 = 0
x = 25 min or 8:25
Max height will occur when -13 ( cos ( pix/60 - 5pi/12) = 13
or in other words, when cos ( pi x / 60 - 5pi/12) = -1 pi x/60 - 5pi/12 = pi x = 85 minutes = 9: 25
Nice job, just one correction. The time for the maximum height is actually 9:25
YOU are right 85 minutes after 8:00 = 9 :25 my bad ! I edited it....thanx for your eagle eye! ~EP