Answer the questions based on the given information
A medicinal drug administered into a human body requires some time to produce its effect on the body. The amount (in mg) of a certain medicinal drug in the bloodstream at t hours after administering the drug to an individual is given by the function:
`C(t) = -t^3 + 4.5 t^2 + 54 t` " " `0 le t le 10`
Shown below is the graph of C(t) in the interval [0, 10].

(i) Find the rate at which the amount of drug is changing in the bloodstream at 5 hours after administering the drug. Show your work.
(ii) Show that the function C(t) is strictly increasing in the interval (3, 4).