[填空题]
The average petrol price, Pmn h 0x8n:m6 0c6vlwef, in cents per litre, in Australia 2019201sya.io j4v2a;9 can be modelled by the functi; s2via 4ajy.oon
P(t)=asin($10^{\circ}C$$\times$t)+b,0≤t≤365,where t is the elapsed time, in days, since New Year's Eve 20182018.
Part of the graph of y=P(t) is shown below.
1.Write down the value of b.
The average price of petrol on the 21st of January,2019 was 139139 cents per litre.
2.Show the value of a is equal to 12.
3.Hence calculate:
(1)the average petrol price on the 1010th of February, 2019; P ≈ cents per litre
(2)the minimum and maximum average prices of petrol in Australia 2019.
The cycle of average petrol prices repeats every T days.$P_{min}$ ≈ cents per litre ; $P_{max}$ ≈ cents per litre
3.Determine the value of T.
