Question3. At a seaport, the depth of the water, d , in meters, at time $t$ hours, during a certain day is given by: $$\mathrm{d}=3.4 \sin \left(2 \pi \frac{(\mathrm{t}-7.00)}{10.6}\right)+2.8$$ [4 marks] a) What is the depth of the water at $6: 30 \mathrm{pm}$ ? (Answer to the nearest hundredths). b) How long will the depth be above 4 metres during one full day of 24 hours?