One hour after a dose of $x$ milligrams of a particular drug is administered to a person, the change in body temperature $T(x)$, in degrees Fahrenheit, is given approximately by
$$
T(x)=x^{2}\left(1-\frac{x}{9}\right) \quad 0 \leq x \leq 7
$$
The rate $T^{\prime}(x)$ at which $T$ changes with respect to the size of the dosage $x$ is called the sensitivity of the body to the dosage.
(A) Use the product rule to find $T^{\prime}(x)$.
(B) Find $T^{\prime}(1), T^{\prime}(3),$ and $T^{\prime}(6)$.