The percent of concentration of a certain drug in the bloodstream x hr after the drug is administered is given by K(x) = 4x . At what time is the concentration a maximum?
X2 + 49
A) 4 hr
B) 4.9 hr
C) 7 hr
D) 2.5 hr

Question

Quizplus · Accepted Answer

The function K(x) = 4x / (x^2 + 49) is a rational function. To find the maximum concentration, take the derivative and set it to zero to find critical points. Solving this, the maximum occurs at x = 7 hr.

The Percent of Concentration of a Certain Drug in the Bloodstream