Lab.
4 & 5: Exponential & Logarithm
Part I :
1) Graph and Compare the following:
a)
and 
b)
and 
c)
and 
d)
and 
e)
and 
2) Graph the following functions:
and
Describe the relation between p and q Find the domain and the
range.
3) Graph the following functions:
and 
a) Describe the difference between f and g
b) Find the domain and the range
4) Solve the following using graphical method:
a) 
b) 
5) There is a mathematical relation between an airplane's weight
x and the runway length required at takeoff. For some airplanes
the minimum runway length in thousands of feet may be modeled
by : ,
where x is measured in thousands of pounds.
a) Graph L
b) Estimate (graphically) and evaluate (algebraically) the
length of the runway when the weight is 10,000 and 100000 pounds.
c) Does the length of the runway from part b) increase by a
factor of 10?
d) Generalize your answer for part b) and c)
Part II
Exponential & Logarithm (Applications)
1) As age increases, so does the likelihood of coronary heart
disease (CHD). The fraction of people x years old with some CHD
is modeled by:

a) Graph f(x)
b) Estimate (graphically) and Evaluate (algebraically) f(25)
and f(65). Compare your estimation with your algebraic results.
c) Interpret the results from part b)
d) Estimate at what age does this likelihood equal 50%?
2)
A) Find an exponential model for the federal debt, based on
the data in the table for Accumulated Gross Federal Debt. Let
x = 0 correspond to 1960.
| Year |
1960 |
1965 |
1970 |
1975 |
1980 |
1985 |
1990 |
1995 |
1996 |
| Amount (billions) |
291 |
322 |
381 |
542 |
909 |
1,818 |
3,207 |
4,921 |
5,182 |
B) Plot both the data points and the model on the same x-y
axis. Describe how well the model matches the data points.
C) Use the model to predict the federal debt in 2002
3) The Drug Medication formula: can
be used to find the number of milligrams D of a certain drug that
is in a patient's bloodstream h hours after the drug has been
administered. When the number of milligrams reaches 2, the drug
is to be administered again. Plot the function D and estimate
the time between injections. (Brain teaser :) After how many hours
will the third injection occur?
4) Stronium-90 is a radioactive material that decay according
to the following function: ,
A0 is the initial amount. A) What is the half-life of stronium-90?
B) Suppose you start with 50 milligrams, graph the function and
use the graph to convince yourself that part A) is the correct
answer. C) Use the graph to estimate when 7 milligrams will remain.
D) Find the exact value for part C)
5) The table shows the number of babies born as twins, triplets,
quadruplets, etc, in recent years.
| Year |
1989 |
1990 |
1991 |
1992 |
1993 |
1994 |
1995 |
| Mult.births |
92,916 |
96,893 |
98,125 |
99,255 |
100,613 |
101,658 |
101,709 |
a) Make a scattered plot of the data.
b) Use the following models and plot each on the same x-y axis
as the data points

c) Which model do you think is a better predictor over the
long run?
d) Use that model to predict the number of multiple births
in 2005
6) A $1000 is invested at a continuously compounding rate of
6% annually. A) Estimate and calculate exactly how long it takes
for that investment to double. Compare your estimate with your
exact value. B) How long it takes that same investment to quadruple.
(show both estimation and exact calculation.). C) When will the
investment reach $12,000?
7) The population of the U.S. is measured every 10 years by the
Census Bureau. The following is a partial list of the census figures.
| Year |
1990 |
1930 |
1950 |
1970 |
1980 |
1990 |
| Pop. In million |
76.1 |
123.2 |
151.7 |
204.9 |
226.5 |
249.6 |
a) Make a scatter plot of the data
b) Find a formula that describes the growth of the population
in the US
c) Plot both the formula and the data on the same x-y-axis
d) Use the formula to predict the population of the US in 2005
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Lab. 4 & 5
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