Population growth

Question

Which is NOT an example of an exponential function?
a.

population growth

c.

compound interest
b.

exponential decay

d.

simple interest

Answer 1

d. simple interest.

Since the interest is not compounding, this is modeled by a linear function, not an exponential function. In both population growth and compound interest, the increase during a given period of time will be added to the base from which further growth will occur in the next period of time. This is the basis of exponential growth. As for exponential decay, this is also an example of an exponential function, in which the amount of decrease is always proportional to the amount remaining. A simple example of exponential decay is the number of players remaining in a single-elimination tournament. After each round, the number of competitors decreases by half.

 

Excellent resource on this topic:

http://www.regentsprep.org/regents/math/algebra/AE7/ExpDecayL.htm