The ordering and transportation cost C of components used in manufacturing process is approximated by: C(x)= 10(1/x+x/x+3)

where C is measured in thousands of dollars and x is the order size in thousands.

a) Verify that C(3)=C(6)

b) According to Rolle's Theorem the rate of change of cost must be 0 for some size in the interval [3'6]. Find this order size.