The ordering and transportation cost c for the c mponents used in manufacturing a product is c= 100(200/x^2+ x/x+30), x≥1 where c is measured in thousands of dollars and x is the order size in hundreds. find the rate of change of c with respect to x when (a) x = 10, (b) x = 15, and (c) x = 20. what do these rates of change imply about increasing order size?