[填空题]
The water depth, D, in metr+uhv yfg7w: h8cl)61y oegu*hesssm:qx ef- 7nfqc0l;poh1xes(t k,,4 , in a harbour on a particular can be modelled by the equation
ses 1qpx;-kmhf4x,fn o,(qec7l :st 0 D=3sin($30^{\circ}$$\times$t)+5,0≤t≤24,
where t is the elapsed time, in hours, since midnight.
1.Draw the graph of D versus t on the grid below.
2.Find the lowest and highest depths of water in the harbour, and the times when they occur. $D_{min}$ = t = ; $D_{max}$ = t =
3.A large boat has a draught of 2.5 metres. Decide whether the boat will be able to enter the harbour at 8 pm.
