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After taking a certain antibiotic, the concentration (C) of the drug in the patient's bloodstream is given by C(x)=(0.04t)/(t2−2), where t is the time (in hours) after taking the antibiotic. How many hours after the antibiotic will its concentration be 0.04 units?

 Oct 18, 2016
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First, that is not a concentration dimension. (.04 units)

But I will assume that you are asking when will C(x) = .04

 

.04 = .04t / (t^2-2)     Multiply both sides by  t^2-2

 

.04t^2 -.08 =.04t

.04t^2-.04t-.08=0     Multiply both sides by 100 (to make it easier to work with it)

4t^2 - 4t - 8 = 0        Now divide by 4

t^2-t-2 = 0

(t-2)(t+1) = 0     means  either t=2  or  -1 hours    -1 hours is not possible, so the only REAL answer is t=2 hours

 Oct 18, 2016

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