1. The percent concentration y of a certain drug in the bloodstream at any time t (in hours) is given by
y = 100(1 - e-0.462t)
(a) What function gives the instantaneous rate of change of the concentration of the drug in the bloodstream?
(b) Find the rate of change of the concentration after 1 hour. Give your answer to three decimal places.
2. Pollution levels in Lake Sagamore have been modeled by the equation
x(t) = 0.05 + 0.18e-0.38t
where x is the volume of pollutants (in cubic kilometers) and t is the time (in years). What is the rate of change of x with respect to time?