The cost of a ride in a taxi is $1.50 for the first half-mile plus a constant amount per half-mile after that. The sequence below shows the pattern of numbers that appear on the driver's screen. 1.50, 2.00, 2.50, 3.00, 3.50, 4.00

Part A: Write a recursive function that can be used to determine f(x), the cost in dollars, for a ride in the taxi of, x, half-miles. Provide mathematical justification for your answer.

Part B: What is the cost, in dollars, for a 10-mile ride in the taxi? Provide mathematical justification for your answer.