1.   Find the critical numbers and the open intervals on which is increasing or decreasing.

2.  Find the critical numbers and the open intervals on which is increasing or decreasing.

3.  Drug Concentration A drug is administered to a patient. A model giving the drug concentration C (in milligrams per milliliter) in the patient’s bloodstream over a 2-hour period is      where t is the time (in minutes).
(a)  Find the intervals on which C is increasing or decreasing.
(b)  Use a graphing utility to graph the function.
(c)  Explain how to use the test for increasing and decreasing functions to determine that the concentration will never reach 120 milligrams.