Final answer:
To represent the total fuel cost in terms of the distance of the trip, we need to define a function, f, that determines the volume of gasoline used in terms of the distance.
Step-by-step explanation:
To represent the total fuel cost in terms of the distance of the trip, we need to define a function, f, that determines the volume of gasoline used in terms of the distance. Let's call the distance of the trip 'd' and the volume of gasoline used 'u'. So the function notation for this would be f(d) = u.
For example, if we define f(100) as the volume of gasoline used for a trip of 100 miles, then we can calculate the fuel cost by multiplying the volume of gasoline used by the cost per gallon.