The body's reaction to medicine dose of medicine can sometimes be represented by an equation of
the form
\begin{equation}
R=M^{2}\left(\frac{C}{2}-\frac{M}{3}\right)
\end{equation}
where $C$ is a positive constant and $M$ is the amount of medicine
absorbed in the blood. If the reaction is a change in blood pressure, $R$ is measured in millimeters of mercury. If the reaction is a change in temperature, $R$ is measured in degrees, and so on.
Find $d R / d M .$ This derivative, as a function of $M,$ is called the sensitivity of the body to the medicine. In Section $4.5,$ we will see how to
find the amount of medicine to which the body is most sensitive.