# Functions 9 - one-to-one Functions

Taught by YourMathGal
• Currently 4.0/5 Stars.
11573 views | 2 ratings
Part of video series
Meets NCTM Standards:
Lesson Summary:

In this lesson on one-to-one functions, the definition, determining whether functions are one-to-one, visual representations, and how to use the horizontal line test are covered. The definition of a one-to-one function is that every input corresponds to only one output, and every output corresponds to only one input. Examples of one-to-one functions are provided, including an ordered pair representation of a polygamous society. The lesson concludes by discussing that the next video will cover inverse functions, which requires knowledge of one-to-one functions.

Lesson Description:

More free YouTube videos by Julie Harland are organized at http://yourmathgal.com

• What is the definition of a one-to-one function?
• How can you determine if a function is 1-1?
• What does a one-to-one function look like?
• What is the horizontal line test for determining if a function is one-to-one?
• What are some examples of real-world 1-1 functions?
• What has to be true for a set of ordered pairs to be a 1-1 function?
• Is a society with polygamy, is marriage a 1-1 function?
• Is the set {(2, -1), (3, 4), (0, 5), (-1, 3)} a 1-1 function?
• Is the set {(4, 3), (3, 4), (-1, 3)} a 1-1 function?
• Is the set {(Tom, Lisa), (Sue, Mary), (Jen, Lisa), (Ed, Cindy)} a 1-1 function?
• How can you use a visual picture to help determine if a function is 1-1?
• #### Staff Review

• Currently 4.0/5 Stars.
This is a very good tutorial explaining what one-to-one functions are, what they look like and behave like, and how to determine if a function is one-to-one. All ideas and concepts of one-to-one functions are explained in this lesson.