Illustrative Math Alignment: Grade 8 Unit 3

Functions and Volume

Lesson 3: Equations for Functions

Use the following Media4Math resources with this Illustrative Math lesson.

Title	Body	Curriculum Topic
Definition--Functions and Relations Concepts--Decreasing Function	Decreasing Function Topic Functions and Relations Definition A decreasing function is a function where the value of the function decreases as the input increases. Description Decreasing functions are important in mathematics because they describe scenarios where an increase in one variable leads to a decrease in another. This is mathematically represented as f(x1) > f(x2) for any 𝑥1 < 𝑥2	Relations and Functions
Definition--Functions and Relations Concepts--Dependent Variable	Dependent Variable Topic Functions and Relations Definition A dependent variable is a variable whose value depends on one or more other variables.	Relations and Functions
Definition--Functions and Relations Concepts--Discontinuous Function	Discontinuous Function Topic Functions and Relations Definition A discontinuous function is a function that has one or more points where it is not continuous.	Relations and Functions
Definition--Functions and Relations Concepts--Discrete Functions	Discrete Functions Topic Functions and Relations Definition Discrete functions are functions that are defined only for a set of discrete points.	Special Functions
Definition--Functions and Relations Concepts--Distorting a Function Horizontally	Distorting a Function Horizontally Topic Functions and Relations Definition Distorting a function horizontally involves stretching or compressing the graph of the function along the x-axis. Description Horizontal distortions of functions are significant because they alter the input values while maintaining the overall shape of the graph. This is mathematically represented as f(kx) where k is a constant. If k > 1, the function compresses horizontally, and if 0 < 𝑘 < 1, it stretches.	Relations and Functions
Definition--Functions and Relations Concepts--Distorting a Function Vertically	Distorting a Function Vertically Topic Functions and Relations Definition Distorting a function vertically involves stretching or compressing the graph of the function along the y-axis. Description Vertical distortions of functions are significant because they alter the output values while maintaining the overall shape of the graph. This is mathematically represented as kf(x)	Relations and Functions
Definition--Functions and Relations Concepts--Domain of a Function	Domain of a Function Topic Functions and Relations Definition The domain of a function is the set of all possible input values (x-values) for which the function is defined.	Relations and Functions
Definition--Functions and Relations Concepts--Even Function	Even Function Topic Functions and Relations Definition An even function is a function that satisfies the condition f(x) = f(−x) for all x in its domain. Description Even functions are important in mathematics because they exhibit symmetry about the y-axis. This property is useful in various fields, including physics and engineering, where symmetry simplifies analysis and problem-solving. For example, the function f(x)=x2	Relations and Functions
Definition--Functions and Relations Concepts--Function	Function Topic Functions and Relations Definition A function is a relation that uniquely associates each element of a set with exactly one element of another set.	Relations and Functions
Definition--Functions and Relations Concepts--Function Machine	Function Machine Topic Functions and Relations Definition A function machine is a conceptual tool used to understand how functions work by visualizing inputs and outputs. Description The function machine is a useful educational tool that helps students grasp the concept of functions by visualizing the process of converting inputs into outputs. It emphasizes the idea that a function takes an input, processes it according to a specific rule, and produces an output. For example, if the function is f(x) = x + 2	Relations and Functions
Definition--Functions and Relations Concepts--Function Notation	Function Notation Topic Functions and Relations Definition Function notation is a way to represent functions in the form f(x), where f denotes the function and x denotes the input variable. Description Function notation is a standardized way to write functions, making it easier to understand and communicate mathematical relationships. It is widely used in algebra, calculus, and other branches of mathematics. For example, the notation f(x) = x2	Relations and Functions
Definition--Functions and Relations Concepts--Function Table	Function Table Topic Functions and Relations Definition A function table is a table that lists input values and their corresponding output values for a given function. Description Function tables are useful tools in mathematics for organizing and analyzing the relationship between inputs and outputs of a function. They help in visualizing how a function behaves and in identifying patterns. For example, a function table for f(x) = 2x + 1	Relations and Functions
Definition--Functions and Relations Concepts--Graphs of Functions	Graphs of Functions Topic Functions and Relations Definition Graphs of functions are visual representations of the relationship between input values and output values of a function. Description Graphs of functions are essential tools in mathematics for visualizing how a function behaves. They provide a clear picture of the relationship between the input and output values, making it easier to analyze and interpret the function. For example, the graph of f(x) = x2	Relations and Functions
Definition--Functions and Relations Concepts--Graphs of Relations	Graphs of Relations Topic Functions and Relations Definition Graphs of relations are visual representations of the relationship between two sets of values, not necessarily functions.	Relations and Functions
Definition--Functions and Relations Concepts--Increasing Function	Increasing Function Topic Functions and Relations Definition An increasing function is a function where the value of the function increases as the input increases.	Relations and Functions
Definition--Functions and Relations Concepts--Independent Variable	Independent Variable Topic Functions and Relations Definition An independent variable is a variable that represents the input or cause and is manipulated to observe its effect on the dependent variable.	Relations and Functions
Definition--Functions and Relations Concepts--Inverse Function	Inverse Function Topic Functions and Relations Definition An inverse function is a function that reverses the effect of the original function, such that f(f−1(x)) = x.	Functions and Their Inverses
Definition--Functions and Relations Concepts--Odd Function	Odd Function Topic Functions and Relations Definition An odd function is a function that satisfies the condition f(−x) = −f(x) for all x in its domain.	Relations and Functions
Definition--Functions and Relations Concepts--Parametric Equations	Parametric Equations Topic Functions and Relations Definition Parametric equations are a set of equations that express the coordinates of the points of a curve as functions of a variable called a parameter.	Relations and Functions
Definition--Functions and Relations Concepts--Piecewise Functions	Piecewise Functions Topic Functions and Relations Definition Piecewise functions are functions defined by multiple sub-functions, each applying to a certain interval of the domain.	Special Functions
Definition--Functions and Relations Concepts--Range of a Function	Range of a Function Topic Functions and Relations Definition The range of a function is the set of all possible output values (y-values) that the function can produce. Description Understanding the range of a function is crucial in mathematics because it defines the scope of possible outputs. The range is determined by the function's rule and the domain. For example, the range of the function f(x) = x2	Relations and Functions
Definition--Functions and Relations Concepts--Recursive Function	Recursive Function Topic Functions and Relations Definition A recursive function is a function that calls itself in its definition. Description Recursive functions are important in mathematics and computer science because they provide a way to solve problems by breaking them down into simpler sub-problems. They are defined by a base case and a recursive case. For example, the factorial function f(n) = n⋅f(n−1) with f(0)=1	Relations and Functions
Definition--Functions and Relations Concepts--Reflecting a Function	Reflecting a Function Topic Functions and Relations Definition Reflecting a function involves flipping the graph of the function over a specified axis. Description Reflecting functions is significant in mathematics because it helps in understanding the symmetry and transformations of functions. A function can be reflected over the x-axis or y-axis, changing its orientation. For example, reflecting the function f(x) = x2	Relations and Functions
Definition--Functions and Relations Concepts--Relation	Relation Topic Functions and Relations Definition A relation is a set of ordered pairs, where each element from one set is paired with an element from another set.	Relations and Functions
Definition--Functions and Relations Concepts--Step Function	Step Function Topic Functions and Relations Definition A step function is a function that increases or decreases abruptly at certain points, creating a series of steps.	Special Functions
Definition--Functions and Relations Concepts--Translating a Function	Translating a Function Topic Functions and Relations Definition Translating a function involves shifting the graph of the function horizontally, vertically, or both, without changing its shape. Description Translating functions is significant in mathematics because it helps in understanding how functions behave under shifts. A function can be translated horizontally by adding or subtracting a constant to the input, and vertically by adding or subtracting a constant to the output. For example, translating the function f(x) = x2 horizontally by 2 units results in	Relations and Functions
Definition--Functions and Relations Concepts--Vertical Line Test	Vertical Line Test Topic Functions and Relations Definition The vertical line test is a method used to determine if a graph represents a function by checking if any vertical line intersects the graph more than once. Description The vertical line test is important in mathematics because it helps in identifying whether a given graph represents a function. If a vertical line intersects the graph at more than one point, then the graph does not represent a function. This test is used in various fields, including computer science for validating functions in programming and in mathematics for analyzing graphs. For example, the graph of	Relations and Functions
Definition--Functions and Relations Concepts--Visual Models of Functions	Visual Models of Functions Topic Functions and Relations Definition Visual models of functions are graphical representations that illustrate the relationship between input and output values of functions. Description Visual models of functions are important in mathematics because they provide a clear and intuitive way to understand how functions behave. These models include graphs, tables, and diagrams that show the relationship between input and output values. For example, the graph of f(x) = x2	Relations and Functions
Definition--Functions and Relations Concepts--Visual Models of Relations	Visual Models of Relations Topic Functions and Relations Definition Visual models of relations are graphical representations that illustrate the relationship between two sets of values, not necessarily functions.	Relations and Functions
Definition--Functions and Relations Concepts--Visualization of the Dependent Variable	Visualization of the Dependent Variable Topic Functions and Relations Definition Visualization of the dependent variable involves graphically representing the outcomes or responses that depend on the independent variable.	Relations and Functions
Definition--Functions and Relations Concepts--Visualization of the Independent Variable	Visualization of the Independent Variable Topic Functions and Relations Definition Visualization of the independent variable involves graphically representing the variable that is manipulated to observe its effect on the dependent variable.	Relations and Functions
INSTRUCTIONAL RESOURCE: Algebra Application: Creating an Exercise Chart	INSTRUCTIONAL RESOURCE: Algebra Application: Creating an Exercise Chart In this Algebra Application, students develop a linear mathematical model based on the maximum heart rate during exercise based on age. Using this model, students investigate heart rate for moderate and vigorous workouts. The math topics covered include: Mathematical modeling, Linear functions, Families of functions, Computational thinking. The culminating activity is for students to create a simple program (using either a spreadsheet or a programming language like Python) to develop an exercise chart. This is a great back-to-school activity for middle school or high school students. A relevant real-world application allows them to review math concepts.	Applications of Linear Functions and Slope-Intercept Form
INSTRUCTIONAL RESOURCE: Algebra Application: Linear Functions: Circumference vs. Diameter	INSTRUCTIONAL RESOURCE: Algebra Application: Linear Functions: Circumference vs. Diameter In this Algebra Application, students study the direction between diameter and circumference of a circle. Through measurement and data gathering students analyze the line of best fit and explore ways of calculating pi. The math topics covered include: Mathematical modeling, Linear functions, Data gathering and analysis, Ratios, Direct variation. This is a great back-to-school activity for middle school or high school students. This is also a great crossover activity that ties algebra and geometry.	Applications of Linear Functions, Applications of Ratios, Proportions, and Percents and Applications of Circles
INSTRUCTIONAL RESOURCE: Tutorial: Analyzing Graphs of Quadratic Functions in Factored Form	INSTRUCTIONAL RESOURCE: Tutorial: Analyzing Graphs of Quadratic Functions in Factored Form This slide show provides 8 examples of quadratic functions in factored form and analyzes their graphs. This is part of a collection of tutorials on a variety of math topics. To see the complete collection of these resources, click on this link. Note: The download is a PPT file. Library of Instructional Resources To see the complete library of Instructional Resources , click on this link.	Quadratic Equations and Functions
INSTRUCTIONAL RESOURCE: Tutorial: Analyzing Graphs of Quadratic Functions in Standard Form	INSTRUCTIONAL RESOURCE: Tutorial: Analyzing Graphs of Quadratic Functions in Standard Form This slide show provides 18 examples of quadratic functions in standard form and analyzes their graphs. This is part of a collection of tutorials on a variety of math topics. To see the complete collection of these resources, click on this link. Note: The download is a PPT file. Library of Instructional Resources To see the complete library of Instructional Resources , click on this link.	Quadratic Equations and Functions
INSTRUCTIONAL RESOURCE: Tutorial: Analyzing Graphs of Quadratic Functions in Vertex Form	INSTRUCTIONAL RESOURCE: Tutorial: Analyzing Graphs of Quadratic Functions in Vertex Form This slide show provides 8 examples of quadratic functions in vertex form and analyzes their graphs. This is part of a collection of tutorials on a variety of math topics. To see the complete collection of these resources, click on this link. Note: The download is a PPT file. Library of Instructional Resources To see the complete library of Instructional Resources , click on this link.	Quadratic Equations and Functions
Instructional Resource: Applications of Linear Functions: Circumference vs. Diameter	In this Slide Show, apply concepts of linear functions to the context of circumference vs. diameter. Note: The download is a PPT file. Related Resources To see the complete collection of Tutorials on this topic, click on this link: https://bit.ly/3g0P3cN	Applications of Linear Functions
Instructional Resource: Applications of Linear Functions: Cost vs. Time	In this Slide Show, apply concepts of linear functions to the context of cost vs. time data and graphs. Note: The download is a PPT file. Related Resources To see the complete collection of Tutorials on this topic, click on this link: https://bit.ly/3g0P3cN	Applications of Linear Functions
Instructional Resource: Applications of Linear Functions: Cricket Chirps	In this Slide Show, apply concepts of linear functions to the context of cricket chirps. Note: The download is a PPT file. Related Resources To see the complete collection of Tutorials on this topic, click on this link: https://bit.ly/3g0P3cN	Applications of Linear Functions
Instructional Resource: Applications of Linear Functions: Distance vs. Time	In this Slide Show, apply concepts of linear functions to the context of distance vs. time data and graphs. Note: The download is a PPT file. Related Resources To see the complete collection of Tutorials on this topic, click on this link: https://bit.ly/3g0P3cN	Applications of Linear Functions
Instructional Resource: Applications of Linear Functions: Hooke's Law	In this Slide Show, apply concepts of linear functions to the context of Hooke's law. Note: The download is a PPT file. Related Resources To see the complete collection of Tutorials on this topic, click on this link: https://bit.ly/3g0P3cN	Applications of Linear Functions and Proportions
Instructional Resource: Applications of Linear Functions: Momentum and Impulse	In this Slide Show, apply concepts of linear functions to the context of momentum and impulse. Note: The download is a PPT file. Related Resources To see the complete collection of Tutorials on this topic, click on this link: https://bit.ly/3g0P3cN	Applications of Linear Functions
Instructional Resource: Applications of Linear Functions: Perimeter of a Rectangle	In this Slide Show, apply concepts of linear functions to the context of rectangular perimeter. Note: The download is a PPT file. Related Resources To see the complete collection of Tutorials on this topic, click on this link: https://bit.ly/3g0P3cN	Applications of Linear Functions
Instructional Resource: Applications of Linear Functions: Saving Money	In this Slide Show, apply concepts of linear functions to the context of saving money. Note: The download is a PPT file. Related Resources To see the complete collection of Tutorials on this topic, click on this link: https://bit.ly/3g0P3cN	Applications of Linear Functions
Instructional Resource: Applications of Linear Functions: Speed and acceleration	In this Slide Show, apply concepts of linear functions to the context of speed and acceleration. Note: The download is a PPT file. Related Resources To see the complete collection of Tutorials on this topic, click on this link: https://bit.ly/3g0P3cN	Applications of Linear Functions
Instructional Resource: Applications of Linear Functions: Temperature Conversion	In this Slide Show, apply concepts of linear functions to the context of converting Celsius and Fahrenheit temperatures. Note: The download is a PPT file. Related Resources To see the complete collection of Tutorials on this topic, click on this link: https://bit.ly/3g0P3cN	Applications of Linear Functions
INSTRUCTIONAL RESOURCE: Desmos Tutorial: Linear Functions in Slope Intercept Form	INSTRUCTIONAL RESOURCE: Desmos Tutorial: Linear Functions in Slope Intercept Form In this Slide Show, use the Desmos graphing calculator to explore linear equations in slope intercept form. To see the complete collection of Desmos Resources click on this link. Note: The download is a PPT file. This is part of a collection of Desmos tutorials on a variety of math topics. To see the complete collection of these resources, click on this link. Library of Instructional Resources To see the complete library of Instructional Resources , click on this link.	Graphs of Linear Functions and Slope-Intercept Form
INSTRUCTIONAL RESOURCE: Desmos Tutorial: Linear Functions in Standard Form	INSTRUCTIONAL RESOURCE: Desmos Tutorial: Linear Functions in Standard Form In this Slide Show, use the Desmos graphing calculator to explore linear equations in standard form. To see the complete collection of Desmos Resources click on this link. Note: The download is a PPT file. This is part of a collection of Desmos tutorials on a variety of math topics. To see the complete collection of these resources, click on this link. Library of Instructional Resources To see the complete library of Instructional Resources , click on this link.	Standard Form
INSTRUCTIONAL RESOURCE: Desmos Tutorial: Matching Coordinates to Absolute Value Functions	INSTRUCTIONAL RESOURCE: Desmos Tutorial: Matching Coordinates to Absolute Value Functions In this Slide Show, use the Desmos graphing calculator to explore absolute value functions. To see the complete collection of Desmos Resources click on this link. Note: The download is a PPT file. This is part of a collection of Desmos tutorials on a variety of math topics. To see the complete collection of these resources, click on this link. Library of Instructional Resources To see the complete library of Instructional Resources , click on this link.	Special Functions
INSTRUCTIONAL RESOURCE: Desmos Tutorial: Matching Coordinates to Linear Functions	INSTRUCTIONAL RESOURCE: Desmos Tutorial: Matching Coordinates to Linear Functions In this Slide Show, use the Desmos graphing calculator to explore linear functions. To see the complete collection of Desmos Resources click on this link. Note: The download is a PPT file. This is part of a collection of Desmos tutorials on a variety of math topics. To see the complete collection of these resources, click on this link. Library of Instructional Resources To see the complete library of Instructional Resources , click on this link.	Applications of Linear Functions