[问答题]
The London Eye is an o
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zt4 .q*lwzh3jervation wheel in England with diameter of 120 metres. The wheel rotates at a constant speed and completes
wj.*4htl3zq z 2.5 rotations every hour. The bottom of the wheel is 15 metres above the ground.
A seat starts at the bottom of the wheel.
1. Find the maximum height above the ground of the seat.
After t minutes, the height h metres above the ground of the seat is given by
h(t)=75+a cos (b t), b>0 .
2. 1. Show that the period of h is 24 minutes.
2. Write down the exact value of b .
3. Find the value of a .
4. Sketch the graph of h , for $0 \leq t \leq 48$ .
5. In one rotation of the wheel, find the probability that a randomly selected seat is at least 110 metres above the ground.
