Learn on PengiCalifornia Reveal Math, Algebra 1Unit 3: Linear and Nonlinear Functions

3-6 Piecewise and Step Functions

In this Grade 9 lesson from California Reveal Math Algebra 1, students learn to identify and graph piecewise-defined functions, piecewise-linear functions, step functions, and the greatest integer function. Students practice graphing multi-rule functions by plotting each piece over its specified domain interval, using open and closed endpoints to indicate strict versus inclusive inequalities. Real-world contexts like swim team age groups help illustrate how step functions model situations where output values change abruptly at defined boundaries.

Section 1

Definition and Notation of Piecewise Functions

Property

A piecewise function is defined by different equations over different intervals of its domain. The general notation is:

f(x)={equation1if condition1equation2if condition2equationnif conditionnf(x) = \begin{cases} \text{equation}_1 & \text{if condition}_1 \\ \text{equation}_2 & \text{if condition}_2 \\ \vdots & \vdots \\ \text{equation}_n & \text{if condition}_n \end{cases}

Examples

Section 2

Graphing Piecewise Functions with Boundary Points

Property

When graphing piecewise functions, use closed circles (•) to indicate points included in the domain of a piece, and open circles (○) to indicate points not included. At boundary points where domain intervals meet, only one piece can contain the boundary value.

Examples

Section 3

Evaluating Piecewise Functions at Specific x-Values

Property

To evaluate a piecewise function at x=ax = a, identify which interval condition aa satisfies, then substitute aa into only that piece's expression.

For a piecewise function such as:

Section 4

Graphing Piecewise Functions

Property

To graph a piecewise function, we plot each piece separately on its specified domain, then combine them into one graph. Each piece is graphed only over its defined interval, and we use open or closed circles to indicate whether endpoints are included.

Examples

Book overview

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Unit 3: Linear and Nonlinear Functions

  1. Lesson 1

    3-1 Graphing Linear Functions

  2. Lesson 2

    3-2 Rate of Change and Slope

  3. Lesson 3

    3-3 Slope-Intercept Form

  4. Lesson 4

    3-4 Transformations of Linear Functions

  5. Lesson 5

    3-5 Arithmetic Sequences

  6. Lesson 6Current

    3-6 Piecewise and Step Functions

  7. Lesson 7

    3-7 Absolute Value Functions

Lesson overview

Expand to review the lesson summary and core properties.

Expand

Section 1

Definition and Notation of Piecewise Functions

Property

A piecewise function is defined by different equations over different intervals of its domain. The general notation is:

f(x)={equation1if condition1equation2if condition2equationnif conditionnf(x) = \begin{cases} \text{equation}_1 & \text{if condition}_1 \\ \text{equation}_2 & \text{if condition}_2 \\ \vdots & \vdots \\ \text{equation}_n & \text{if condition}_n \end{cases}

Examples

Section 2

Graphing Piecewise Functions with Boundary Points

Property

When graphing piecewise functions, use closed circles (•) to indicate points included in the domain of a piece, and open circles (○) to indicate points not included. At boundary points where domain intervals meet, only one piece can contain the boundary value.

Examples

Section 3

Evaluating Piecewise Functions at Specific x-Values

Property

To evaluate a piecewise function at x=ax = a, identify which interval condition aa satisfies, then substitute aa into only that piece's expression.

For a piecewise function such as:

Section 4

Graphing Piecewise Functions

Property

To graph a piecewise function, we plot each piece separately on its specified domain, then combine them into one graph. Each piece is graphed only over its defined interval, and we use open or closed circles to indicate whether endpoints are included.

Examples

Book overview

Jump across lessons in the current chapter without opening the full course modal.

Continue this chapter

Unit 3: Linear and Nonlinear Functions

  1. Lesson 1

    3-1 Graphing Linear Functions

  2. Lesson 2

    3-2 Rate of Change and Slope

  3. Lesson 3

    3-3 Slope-Intercept Form

  4. Lesson 4

    3-4 Transformations of Linear Functions

  5. Lesson 5

    3-5 Arithmetic Sequences

  6. Lesson 6Current

    3-6 Piecewise and Step Functions

  7. Lesson 7

    3-7 Absolute Value Functions