find C'(x), set it equal to 0, and solve for x.
where are you experiencing difficulty?
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.