Question

The function D(h) = 7e^(-0.4h) can be used to determine the milligrams D of a certain drug in a patient's bloodstream h hours after the drug has been given. How many milligrams (to two decimals) will be present after 9 hrs

Answer 1

Given the function:

$D(h)=7e^{-.04h}$

we can find how many miligrams will be present after 9 hours by making h = 9 and evaluating on the function to get the following:

$\begin{gathered} h=9 \\ \Rightarrow D(9)=7e^{-0.4\cdot9}=7e^{-3.6}=0.19 \\ \end{gathered}$

therefore, there will be 0.19 miligrams after 9 hours