Recognizing functions

9 videos
2 skills
Relationships can be any association between sets of numbers while functions have only one output for a given input. This tutorial works through a bunch of examples of testing whether something is a valid function. As always, we really encourage you to pause the videos and try the problems before Sal does! Common Core Standard: 8.F.A.1

Testing if a relationship is a function

VIDEO 2:23 minutes
Sal determines if points on a graph represent a function.

Relations and functions

VIDEO 6:57 minutes
Sal determines if a relation given by a set of ordered pairs is a function.

Checking if a set of points represents a function

VIDEO 4:07 minutes
Sal checks whether a given set of points can represent a function. For the set to represent a function, each domain element must have one corresponding range element at most.

Checking if a table represents a function

VIDEO 1:16 minutes
Sal determines if y is a function of x from looking at a table.

Recognize functions from tables

PRACTICE PROBLEMS
Determine whether a table of values of a relationship represents a function.

Is this a function? (verbal description of equation)

VIDEO 1:31 minutes
Sal checks whether y can be described as a function of x if y is always three more than twice x.

Checking if two quantities represents a function: heights

VIDEO 4:40 minutes
Sal checks whether a table of people and their heights can represent a function that assigns a height to a name.

Checking if two quantities represents a function: price & cost

VIDEO 3:23 minutes
Sal checks whether a description of the price of an order can be represented as a function of the shipping cost.

Checking if an equation represents a function

VIDEO 3:33 minutes
Sal determines if y is a function of x from looking at an equation.

Does a vertical line represent a function?

VIDEO 1:40 minutes
Sal explains why a vertical line *doesn't* represent a function.

Recognize functions from graphs

PRACTICE PROBLEMS
Determine whether a given graph represents a function.