The function

represents the distance d, in miles, from the airport after t minutes of an airplane asked to fly in a circular holding pattern.

(a) What is the plane’s average distance from the airport over one cycle?

(b) How long does it take the plane to complete one cycle in the holding pattern?

(c) What is the plane’s speed, in miles per hour, while in the holding pattern?

(d) If the plane travels 1.8 miles per gallon of fuel, how much fuel is used in one cycle of the holding pattern?

d(t) = 50 cos(+6 + 60