Section 9A Practice

What is the purpose of a function?

• A function describes how inputs and outputs are affected by machines.

• A function describes an operation, such as multiplication or division.

• A function describes how one variable depends on another.

• A function describes how a domain and a range interact with one another.

What does the fact that the Dow Jones Industrial Average (DJIA) changes from day to day say?

• The DJIA is a function of time because time, the dependent variable changes with respect to the DJIA, the independent variable.

• Time is a function of the DJIA because time, the dependent variable, changes with respect to the DJIA, the independent variable.

• Time is a function of the DJIA because the DJIA, the dependent variable, changes with respect to time, the independent variable.

• The DJIA is a function of time because the DJIA, the dependent variable, changes with respect to time, the independent variable.

Tags

TEKS.MATH.A.12B

Which variable is plotted on the vertical axis when a graph of the function z = f (w) is created?

• z is plotted on the vertical axis because the horizontal axis is used for the dependent variable and the vertical axis is used for the independent variable.

• w is plotted on the vertical axis because the horizontal axis is used for the independent variable and the vertical axis is used for the dependent variable.

• z is plotted on the vertical axis because the horizontal axis is used for the independent variable and the vertical axis is used for the dependent variable.

• f is plotted on the vertical axis because the horizontal axis is used for the dependent variable and the vertical axis is used for the independent variable.

Consider a function that describes how a particular car's gas mileage depends on its speed. What would an appropriate domain for this function be?

• An appropriate domain would be times from 0 to 10 minutes because the time is the dependent variable of the function, and the domain consists of all reasonable values of the dependent variable.

• An appropriate domain would be 0 to 50 miles per gallon because the gas mileage is the independent variable of the function, and the domain consists of all reasonable values of the independent variable.

• An appropriate domain would be 0 to 100 miles per hour because the speed is the independent variable of the function, and the domain consists of all reasonable values of the independent variable.

Tags

TEKS.MATH.2A.2A

TEKS.MATH.2A.7I

TEKS.MATH.A.2A

TEKS.MATH.A.6A

TEKS.MATH.A.9A

What is a mathematical model?

• Mathematical models are based on relationships between quantities that remain constant and can only be described by a graph.

• Mathematical models are based on relationships between quantities that change and are described by very complicated functions that can only be understood using supercomputers.

• Mathematical models are based on relationships between quantities that change and are described by mathematical tools called functions.

• Mathematical models are based on relationships between quantities that remain constant and are described by mathematical tools called functions.

Tags

TEKS.MATH.AR.7B

What are the three basic ways to represent a function?

• The three basic ways to represent a function are a table, a graph, and an expression.

• The three basic ways to represent a function are an ordered pair, a graph, and an expression.

• The three basic ways to represent a function are a table, a graph, and an equation.

• The three basic ways to represent a function are a table, an ordered pair, and an equation.

Tags

TEKS.MATH.A.2C

Graph the points on the same axes.

A(4, 2 ), B( − 7, 3 ),

C(1, 0 ), D( − 3, − 1 )

Tags

TEKS.MATH.6.11A

In the following situation, state whether two variables are related in a way that might be described by a function.

You make a list of 5 friends'/ families' names and all 17 of their e-mail addresses.

• The situation cannot be described by a function

• The situation can be described by a function. The dependent variable is your friends'/ families' names and the independent variable is the e-mail addresses.

• The situation can be described by a function. The dependent variable is the e-mail addresses

  and the independent variable is your friends'/ families' names.

• The situation can be described by a function. There is a dependent variable, but no independent variable. The dependent variable is your friends'/ families' names.

Tags

TEKS.MATH.8.5G

TEKS.MATH.A.12A

In the following situation, state whether two variables are related in a way that might be described by a function.

You run an electronic store and want to know how the quantity of TVs you sell depends on the price you charge per TV.

• The situation cannot be described by a function.

• The situation can be described by a function. There is a dependent variable, but no independent variable. The dependent variable is TVs sold.

• The situation can be described by a function. The dependent variable is the TVs sold and the independent variable is the price.

• The situation can be described by a function. The dependent variable is the price and the independent variable is the TVs.

Tags

TEKS.MATH.8.5G

TEKS.MATH.A.12A

Write a short statement that expresses a possible relationship between the variables.

(volume of gas tank, cost to fill the tank)

• As the volume of a gas tank increases, the cost to fill the tank increases.

• As the cost to fill a gas tank increases, the volume of a gas tank decreases.

• As the volume of a gas tank increases, the cost to fill the tank decreases.

• As the cost to fill a gas tank increases, the volume of a gas tank increases.

Tags

TEKS.MATH.6.7B