The function gives the cost to manufacture x items.

Question

C(x) = 20,000 + 5x −
x2
20,000
; x = 20,000
Find the average cost per unit of manufacturing h more items (i.e., the average rate of change of the total cost) at a production level of x, where x is as indicated and h = 10 and 1. (Use smaller values of h to check your estimates.) HINT [See Example 1.] (Round your answers to five decimal places.)
h 10 1
Cave 1 2

Estimate the instantaneous rate of change of the total cost at the given production level x, specifying the units of measurement.
C'(20,000) = 3