Over a 28 day period, the cost per litre of petrol was modelled by C(t)=9.2sin(7π(t−4))+107.8 cents L−1.
a. True or false?
- “The cost per litre oscillates about 107.8 cents with maximum price $1.17 per litre.”
- “Every 14 days, the cycle repeats itself.”
b. What was the cost of petrol on day 7, to the nearest tenth of a cent per litre?
c. On which days was the petrol priced at $1.10 per litre?
d. What was the minimum cost per litre and when did it occur?