Student Goal

I can identify exponential relationships and interpret the starting value and growth factor.

Why It Matters

Exponential relationships describe situations like doubling, repeated percent change, savings growth, and decay.

Warm-Up

Warm-Up 1

Which pattern is exponential?

Warm-Up 2

In y = 5(2)^x, what is the starting value?

Short Lesson

Standard Focus

NC.M1.F-LE.1 and NC.M1.F-LE.2: Exponential functions

Student-Friendly Standard Goal

I can distinguish linear and exponential relationships and build simple exponential models.

  • Exponential relationships multiply by the same factor each step.
  • Linear relationships add the same amount each step.
  • A simple exponential model has the form y = a(b)^x.
  • a is the starting value and b is the growth or decay factor.

Guided Examples

Guided Example 1

Identify the Growth Factor

The table shows an exponential pattern. Find the growth factor.

Step 1

4, 12, 36, 108

What do you multiply by each step?

Guided Example 2

Compare Linear and Exponential

Which relationship is exponential?

Step 1

Table A: 2,5,8,11

What kind of pattern is Table A?

Practice

Problem 1

Which sequence has a common ratio of 4?

Problem 2

In y = 12(0.5)^x, the relationship shows...

Problem 3

For y = 3(2)^x, find y when x = 2.

Problem 4

Error analysis: A student says 5, 10, 15, 20 is exponential because it increases. What is wrong?

Problem 5

True or false: 1, 3, 9, 27 is exponential.

Reflection

How are you feeling about today's skill?

Optional reflection: What is one step, word, or representation from today that you want to remember when Math 1 starts?