case 1

The meaning of exponents (Slides 1-9)
Multiple factors (Slides 10-13)
Comparing Linear and Exponential Growth (Slides 14-29)
Partial Factors and Creating Formulas (Slides 30-36)
Increasing Compounding Periods (Slides 37-43)
Focus on Formulas and Motivatinge (Slides 44-48)
Exploring Continuous Growth and Decay (Slides 49-51)
Average Rate of Change (Slides 52-62)
Connecting to Proportionality (Slides 63-70)
Introduction to Logarithms (Slides 71-82)
Applications of Logarithms (Slides 83-91)

The meaning of exponents (Slides 1-9): Click for Purpose
Purpose: This section will introduce students to exponential growth in a situation the students can model. They will be exposed to the motivation behind the notation for exponents and their meaning. They will also beging to look at the form of a function that represents a situation involving repeated multiplication (in this case doubling).
Worksheet 1
Notes
Click for Summary/Goals
  • Students will explore how exponential functions grow
  • They will come to understand exponential notation
  • Create an exponential function to model the situation
Click for Implementation Notes
  • This worksheet should be given at the beginning of slide 2
  • The teacher should emphasize teh idea of doubling for each square
  • The teacher should emphasize the notation for repeated multiplication (exponents)
  • Recommended time: 15 minutes

Multiple factors (Slides 10-13): Click for Purpose
Purpose: Students will explore what happens when there are different growth factors. The students will have to use properties of exponents and should develop a foundation for understanding fractionaly exponents.
Worksheet 2
Notes
Click for Summary/Goals
  • Students will explore different growth factors
  • Students will create a meaningful understanding of the properties of exponents
Click for Implementation Notes
  • This worksheet should be given at the beginning of slide 10
  • Each group should pick a different sized "chunk" of squares
  • The teacher should encourage students to think about how the size of the "chunk" impacts their growth factor
  • The meaning of exponents and need for exponential behavior should be emphasized throughout the worksheet
  • Recommended time: 15 minutes

Comparing Linear and Exponential Growth (Slides 14-29): Click for Purpose
Purpose: Students will get to explore a situation in which there is both a constant rate of change and a constant percentage change. They will explore the similarities and differences in the growth patterns. This will help students understand the difference between the two types of growth as well as understand how a growth factor works.
Worksheet 3
Notes
Click for Summary/Goals
  • Students will construct a growth factor for the exponential situation
  • Students will connect the patterns in each situation with the function type
  • Students will explore how the exponential situation changes if the initial value is changed
  • Students will create a formula for each situation
  • Students will explore each situation in multiple representations
Click for Implementation Notes
  • This worksheet should be given during slide 14
  • The teacher should probe students about how successive outputs are related in each situation
  • Students may use graphing calculators to produce the graphs
  • The teacher should ask the students to give the domain and range for the situation
  • Recommended time: 15 minutes

Partial Factors and Creating Formulas (Slides 30-36): Click for Purpose
Purpose: The students will become familiar with the notion of repeated multiplication for various time intervals. Also they will become comfortable with expressing exponents as rational numbers.
Worksheet 4
Notes
Click for Summary/Goals
  • Students will become familiar with using rational numbers as exponents
  • Students should be able to explain how a rational exponent affects the growth factor
Click for Implementation Notes
  • This worksheet should be given during slide 30
  • The teacher should make sure student responses are given in terms of repeated multiplication
  • It may be useful to have the students build a table for 10 minute time intervals
  • Recommended time: 15 minutes

Increasing Compounding Periods (Slides 37-43): Click for Purpose
Purpose: This section will allow students to explore what happens when there are additional compounding periods and how it affects the basic investment formula. They will get to create the general investment formula and determine growth factors for various compounding periods. This section will also serve as a lead in to their investigations into e.
Worksheet 5
Notes
Click for Summary/Goals
  • The students will explore how different compounding periods affect the growth factor of their exponential functions
  • The students will come up with the general investment formula
  • The students will explore what happens to their outputs when their initial investment is changed
  • The students will explore what happens to their outputs when their compounding period is changed
Click for Implementation Notes
  • This worksheet should be given prior to slide 38
  • The teacher should make sure the students look at the ratio when determining the data is exponential
  • The teacher should reinforce the meaning of growth factor during this worksheet
  • Recommended time: 15 minutes

Focus on Formulas and Motivating e (Slides 44-48): Click for Purpose
Purpose: This section will introduce the students to the natural base, e, by building off of their investigations in worksheet 5. This will give them an understanding of where e comes from and how the formula for continuous growth/decay is derived.
Worksheet 6
Notes
Click for Summary/Goals
  • Students will gain a deeper understanding of how the compound interest formula works
  • Students will investigate what happens with the growth factor as the number of compouning periods increases (eventually without bound)
  • Students will see the derivation of the formula for continuous growth/decay
Click for Implementation Notes
  • This worksheet should be given at the beginning of slide 44
  • The teacher should reinforce the meaning of growth factor during this worksheet
  • The teacher should lead the students to understanding the limiting value in the growth factor
  • Recommended time: 15 minutes

Exploring Continuous Growth and Decay (Slides 49-51): Click for Purpose
Purpose: The students will have the opportunity to model situations involving continuous growth and decay. They will apply the formulas they derived in the previous worksheet and use them to reason about the situations being modeled. They will also find and reason about the growth/decay factors in these situations.
Worksheet 7
Notes
Click for Summary/Goals
  • The students will create exponential functions to model situations involving continuous growth/decay
  • The students will reason about these situations
  • The students will identify the growth/decay factors in these situations and describe their meaning
Click for Implementation Notes
  • This worksheet should be given prior to slide 50
  • The teacher should ensure the students realize the significance of having a continuous growth rate
  • The teacher should probe the students about the meaning of the growth factor until their responses are in terms of repeated multiplication
  • Recommended time: 15 minutes

Average Rate of Change (Slides 52-62): Click for Purpose
Purpose: This section will allow students to investigate how the rate of change is related to the amount of an exponential function. The students will explore the rate of change of an investment that is growing exponentially and its relationship to the account balance at the beginning of the interval. This will build the foundation for students understanding that the rate of any exponential function is always proportional to its amount.
Worksheet 8
Notes
Click for Summary/Goals
  • Students will explore the relationship between an account balance and the rate is increasing
  • Students will discuss the meaning of average rate of change in this context
  • Students will explore the pattern in the average rates of change for successive intervals
Click for Implementation Notes
  • This worksheet should be given prior to slide 53
  • The teacher should probe students about the average rate of change in this context until their answers are given number of squares and number of pennies
  • The teacher should ensure that the students are seeing the pattern in the average rate of change
  • Recommended time: 15 minutes

Connecting to Proportionality (Slides 63-70): Click for Purpose
Purpose: This section will extend students' understanding of the proportional relationship between the amount of an exponential function and the rate that it is increasing/decreasing. They will also find the constant of propotionality and see how it is related to the situation.
Worksheet 9
Notes
Click for Summary/Goals
  • Students will investigate the proportionality between amount and rate of an exponential situation
  • Students will find the exact factor, k, or constant of proportionality and discuss how it relates to the situation
Click for Implementation Notes
  • This worksheet should be given at the beginning of slide 63
  • The teacher should emphsize the ideas of rate and proportionality
  • The teacher should ensure that students discuss rate in terms of the context
  • The teacher should have students find the exact value for the constant of proportionality and describe how it relates to the situation
  • Recommended time: 15 minutes

Introduction to Logarithms (Slides 71-82): Click for Purpose
Purpose: This section will introduce students to logarithms as the inverse of exponential functions. Students should come to see logarithms as exponents. They will explore how to change between logarithmic form and exponential form. There will still be an emphasis on multiplicative thinking, but now the focus will be logarithmic, or the inverse.

Applications of Logarithms (Slides 83-91): Click for Purpose
Purpose: This section will help deepen the students understanding of logarithms. They will use logarithms to solve problems in which the exponent is unknown. They will revisit some of the earrlier applications and be introduced to the concept of half-life.

 

Return to Support Home