1 MAC1105, College Algebra Study Questions for Common Final ...

34. Fill in the following chart and then construct exponential functions for each part (a) to (g).
Initial
Value
a. 600
b. 1200
Growth or
Decay?
c. 6000 Decay
d. 1,500,000 Decay
e. 1,500,000 Growth
f. 7
g. 60
Growth or
Decay Factor
2.06
4.35
0.35
10
Growth or
Decay Rate (% form)
200%
75%
25%
25%
Exponential
Function
35. The table below represents an exponential function. Construct that function and then identify
the corresponding growth or decay rate in percentage form.
X 0 1 2 3
Y 500.00 425.00 361.25 307.06
36. Generate equations that represent the pollution levels, P(t), as a function of time, t (in years),
such that P(0) = 150 and:
a. P(t) triples each year.
b. P(t) decreases by twelve units each year.
c. P(t) decreases by 7% each year.
d. The annual average rate of change of P(t) with respect to t is constant at 1.
37. A pollutant was dumped into a lake, and each year its amount in the lake is reduced by 25%.
a. Construct a general formula to describe the amount of pollutant after t years if the
original amount is .
b. Use a symbolic approach to determine how long it will take before the pollution is
reduced to 10% of its original level.
38. Which of the following functions have a fixed doubling time? A fixed half-life?
a. Y = 62 c. Q = 300(1/2) t e. P = 500 – ½ T
b. Y = 5 + 2x d. A = 102
f. N = 50(
)t/20