Given function:
[tex]D(t)=5e^{-0.4t}[/tex]Where D is the number of milligrams of drugs
t is time
(a) The initial amount of drug administered.
The initial amount of drug administered is the drug administered at t = 0
Hence:
[tex]\begin{gathered} D(t=0)\text{ = 5 }\times e^{-0.4\times0} \\ =\text{ 5 milligrams} \end{gathered}[/tex](b) The number of milligrams that would be present after 1 hour
Here, we substitute 1 for t into the function:
Functional notation:
[tex]D(t=1)\text{ =5}\times e^{-0.4\times1}[/tex]Calculated Value:
[tex]D(t=1)\text{ = 3.35 milligrams}[/tex](c) The number of milligrams present after 8 hours:
[tex]\begin{gathered} D(t=8)\text{ = 5}\times e^{-0.4\times8} \\ =\text{ 0.20 milligrams} \end{gathered}[/tex]