Math 155-004, Quiz 3 February 10, 2009 NAME:

Math 155-004, Quiz 3
February 10, 2009
Instructions: This quiz is closed books and closed notes. You may use calculators. Work that is erased or
crossed out will not be graded.
1. [1.7 Ex. 29] (5 pts) Consider the function S(t) = 3e0.2t . (i) Is S(t) increasing or decreasing? (ii) Graph
the function. (iii) Graph a semilog plot of the function. (iv) If the function is increasing, find the doubling
time; if it is decreasing, find the half-life. (v) For what value of t does S(t) = 12?
2. (3 pts) Let f (x) = −2 + 3 cos(2t − 4). Give values for the following:
average value:
maximum value:
3. (2 pts) Write a formula for the weighted average of two values x and y with weight q.
Extra Credit: Fill in the blank: Cisne developed mathematical models for
that were informed by models for populations of organisms.