The demand function for the Sicard sports watch is given by

d(x) =45/0.01x²+ 1. (0x20)

wherex(measured in units of a thousand) is the quantity demanded per week andd(x) is the unit price in dollars.

(a) Findd'(x).

d'(x) =

(b) Find the following values in dollars per thousand watches. (Round your answers to two decimal places.)

d'(5)=$ per thousand watches

d'(10)=$ per thousand watches

d'(18)=$ per thousand watches