A device that monitors rotational vibration changes in turbines may be pur- EXAMPLE chased for use in southern California wind farms. The first cost is $40,000 with a constant AOC of $15,000 over a maximum service period of 6 years. Use the decreasing future market values and i = 20% per year to find the best n value for an economic evaluation. After k years of service 2 3 4 5 6 Estimated market value is $32,000 30,000 24,000 20,000 11,000