# Recognizing functions

9 videos
2 skills
Not all relationships are functions. In this tutorial, you'll learn which are!

### Testing if a relationship is a function

VIDEO 2:23 minutes
Testing if a relationship is a function

### How to check if a set of points on the graph represents a function (example)

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.

### Functions as graphs

VIDEO 9:35 minutes

### How to check if a relationship between variables described verbally represents a function (example)

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.

### Does a vertical line represent a function?

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

### How to check if a table represents a function (example)

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.

### Recognizing functions (example 3)

VIDEO 1:16 minutes

### Recognizing functions from tables

PRACTICE PROBLEMS
Determine if different relationships are functions or not.

### Recognizing functions (example 4)

VIDEO 3:33 minutes

### How to check if a relationship between real-world quantities described verbally represents a function (example)

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.

### Recognizing functions from graphs

PRACTICE PROBLEMS