<img src="https://d5nxst8fruw4z.cloudfront.net/atrk.gif?account=iA1Pi1a8Dy00ym" style="display:none" height="1" width="1" alt="" />

# Exponential Models

## Population and investing using exponential functions.

Estimated11 minsto complete
%
Progress
Practice Exponential Models
Progress
Estimated11 minsto complete
%
Exponential and Logarithmic Models

Feel free to modify and personalize this study guide by clicking “Customize.”

### Vocabulary

##### Complete the table.
 Word Definition ______________ to create new data points, or to predict, outside of the domain of the data set Interpolate ______________________________________________________________________ ______________ a solution to a function that is not useful in the given context Exponential Model ______________________________________________________________________

### Models

A population which increases continuously at a constant rate may be modeled with an exponential function.

A population which increases rapidly and then levels off may be modeled with a logarithmic function.

#### Exponential

The equation for population growth is: $P(f) = P_i \cdot r^{x}$

What does each letter in the equation mean? ______________  ______________  ______________  ______________

This equation is used in countless situations besides population growth. What are some situations in which you would use that equation? ________________________________________________________

.

For problems 1-3, calculate:

a) The growth factor

b) The final population

1. If a population starts at 5,000 people in 1990, and increases at a rate of 9% per year, what is the population in 2037?
2. If a population starts at 15,000 people in 2000, and increases at a rate of 6% per year, what is the population in 2019?
3. If a population starts at 25,500 people in 1900, and increases at a rate of 4% per year, what is the population in 2004?

#### Logarithmic

To solve complex logarithmic equations, you must use your knowledge from algebra as well as the logarithmic properties

What are three logarithmic properties?

1) ____________________________________

2) ____________________________________

3) ____________________________________

.

Solve for $x$

1. $4 log (\frac{x}{5}) + log (\frac{625}{4}) = 2 log x$
2. $log_5 z + \frac{log_5 125}{log_5 x} = \frac{7}{2}$
3. $log p = \frac{2 - log p}{log p}$
4. $2 log x - 2 log (x+1) = 0$
5. $log (25 - z^3) - 3log (4 - z) = 0$
6. $\frac{log (35 - y^3)}{log (5 - y)} = 3$