Evaluating an exponential function with base e that models a real-world.

The number of milligrams $D(h)$ of a drug in a patient's bloodstream $h$ hours after the drug is injected is modeled by the following functio
\[
D(h)=45 e^{-0.3 h}
\]

Find the initial amount injected and the amount in the bloodstream after 6 hours.
Round your answers to the nearest hundredth as necessary.
Initial amount:
milligrams
Amount after 6 hours:
milligrams

Step 1 ：The number of milligrams $D(h)$ of a drug in a patient's bloodstream $h$ hours after the drug is injected is modeled by the function $D(h)=45 e^{-0.3 h}$.

Step 2 ：The initial amount of the drug can be found by evaluating the function at $h=0$.

Step 3 ：The amount of the drug after 6 hours can be found by evaluating the function at $h=6$.

Step 4 ：Calculating these values, we find that the initial amount is 45.0 milligrams and the amount after 6 hours is approximately 7.44 milligrams.

Step 5 ：Final Answer: The initial amount of the drug injected is \(\boxed{45.00}\) milligrams and the amount in the bloodstream after 6 hours is approximately \(\boxed{7.44}\) milligrams.