Solutions Wksts Ch7
ANSWERS page 1
page 2
ELL Support
7-1
7-1
Exploring Exponential Models
exponential function
exponential growth
exponential decay
growth factor
decay factor
1. Is an exponential model reasonable for this situation? Explain.
1. In the function y 5 12(2.3)x , the value 2.3 is the growth factor . asymptote 2. An
Yes; the population decreases at a fixed, constant rate of 3.5% per year.
is a line that a graph approaches as x or y increases in
An exponential model is reasonable
absolute value. exponential decay
3. For
Exploring Exponential Models
Population The population of a certain animal species decreases at a rate of 3.5% per year. You have counted 80 of the animals in the habitat you are studying.
a. Write a function that models the change in the animal population.
b. Graphing Calculator Graph the function. Estimate the number of years until the population first drops below 15 animals.
Choose the word or phrase from the list that best completes each sentence.
asymptote
Think About a Plan
.
a(1 1 r) z
2. Write the function that models exponential growth or decay. A(t) 5 z t , as the value of x increases, the value of y
decreases.
4. A function in the general form y 5 abx is called an exponential function .
animals z .
3. The initial population is z 80
5. For exponential growth , as the value of x increases, the value of y
4. Is the rate of change positive or negative? Explain.
increases.
The population is decreasing, so the rate of change is negative
6. In the function y 5 4(0.3)x , the value 0.3 is the
decay factor
.
z
.
z
5. The rate of change is 20.035 .
Identify whether each function represents exponential growth or exponential decay. 7. y 5 0.75(4)x
exponential growth
8. y 5 0.63(0.5)x
exponential decay
9. y 5 9(0.83)x
exponential decay
t
6. Write a function that models the change in the animal population. P(t) 5 z 80(0.965) z
7. Graph your function on a graphing calculator. Sketch
page 2
ELL Support
7-1
7-1
Exploring Exponential Models
exponential function
exponential growth
exponential decay
growth factor
decay factor
1. Is an exponential model reasonable for this situation? Explain.
1. In the function y 5 12(2.3)x , the value 2.3 is the growth factor . asymptote 2. An
Yes; the population decreases at a fixed, constant rate of 3.5% per year.
is a line that a graph approaches as x or y increases in
An exponential model is reasonable
absolute value. exponential decay
3. For
Exploring Exponential Models
Population The population of a certain animal species decreases at a rate of 3.5% per year. You have counted 80 of the animals in the habitat you are studying.
a. Write a function that models the change in the animal population.
b. Graphing Calculator Graph the function. Estimate the number of years until the population first drops below 15 animals.
Choose the word or phrase from the list that best completes each sentence.
asymptote
Think About a Plan
.
a(1 1 r) z
2. Write the function that models exponential growth or decay. A(t) 5 z t , as the value of x increases, the value of y
decreases.
4. A function in the general form y 5 abx is called an exponential function .
animals z .
3. The initial population is z 80
5. For exponential growth , as the value of x increases, the value of y
4. Is the rate of change positive or negative? Explain.
increases.
The population is decreasing, so the rate of change is negative
6. In the function y 5 4(0.3)x , the value 0.3 is the
decay factor
.
z
.
z
5. The rate of change is 20.035 .
Identify whether each function represents exponential growth or exponential decay. 7. y 5 0.75(4)x
exponential growth
8. y 5 0.63(0.5)x
exponential decay
9. y 5 9(0.83)x
exponential decay
t
6. Write a function that models the change in the animal population. P(t) 5 z 80(0.965) z
7. Graph your function on a graphing calculator. Sketch