Reading Questions over Section 4.2  Name___________________________

1. In Example 2, a model for the US population is given. Use this model to approximate,
to the nearest million, the population of our country in 2050. ___________
 

2. For Example 2, use logarithms to determine the value of t for which P = 300.
Report your answer exactly (involving a logarithm) as well as an approximation accurate to 2 decimal places.
Show work, as done on page 160:

Exact answer:                                     Approximate answer:

3. The mathematical model in Example 2 gave t in years since Jan.1, 2006.
What month does the model predict that P = 300?  _____________
Note: The US population officially celebrated turning 300 million on October 17, 2006.

4. The doubling time of a quantity is ...
o the time it takes for the quantity to grow by 50%
o the time it takes for the quantity to grow by 100%
o the time it takes for the quantity to grow by 200%

5. Look at the graph of the function P = 25(1.075)^t in Problem 31 on page 158.
Use the graph to estimate the doubling time of P.  t = ___________
  

6. Look at the graph of the function Q= 10e^0.15t in Problem 32 on page 158.
Use the graph to estimate the half-life of Q.   t = ___________

7. Read Example 12 very carefully. Why didn't they solve it using logs?
Pick the best answer.
o they could have, but the authors preferred to use the graphical approach instead.
o it is not possible to solve this problem with logs.
o they were just plain lazy
o the problem cannot be solved by any method.  There is no solution.
o it would have required taking the logarithm of 0 which is undefined.