Question

LOGARITHMS, CONIC SECTIONS, SEQUENCES

Evaluating an exponential function with base e that models a real...
The number of milligrams D (n) of a drug in a patient's bloodstream h hours after the drug is injected is modeled by the following function.
D(h) =40e-0.5h
Find the initial amount injected and the amount in the bloodstream after 7 hours.
Round your answers to the nearest hundredth as necessary.
Initial amount:
milligrams
Amount after 7 hours:
milligrams
X
5
?
Explanation
Check
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Answer 1

(a) 40 milligrams

(b) 1.21 milligrams

Explanation:

Exponential Function

It's commonly used to model real situations in life, like this one proposed in the question where the number of milligrams of a drug D(h) in a patient's bloodstream h hours after the drug is injected is modeled by the following function.

`D(h) =40e^(-0.5h)`

(a) The initial amount injected to the patient can be found when h=0

`D(0) =40e^(-0.5(0))=40e^(0)=40`

Initial amount: 40 milligrams

(b) Let's plug h=7

D(7) =40e^{-0.5(7)}=40e^{-3.5}=1.21

The amount in the bloodstream after 7 hours is 1.21 milligrams