# A.4.1 Learning Goals

- Author:
- Katie Akesson

__Learning Goals__

- I can explain when a relationship between two quantities is a function.
- I can identify independent and dependent variables in a function, and use words and graphs to represent the function.
- I can make sense of descriptions and graphs of functions and explain what they tell us about situations.

__Glossary__dependent variable - a variable (often denoted by

*y*) whose value depends on that of another, it represnts the output of a function. function - takes inputs from one set and assigns them outputs from another set, assigning exatly one output to each input. independent variable - a variable (often denoted by

*x*) whose variation does not depend on that of another, it represnts the input of a function (you can choose the value for it).

Using the example in the opener about number of bagels and price, lets look at a situation that

*is*a function and one that*is not*a function. Because there are multiple possible prices when the number of bagels is 6 or greater,**price***is not*a function of the number of bagels bought. Because there is only one best price for a particular number of bagel,**best price***is*a function of the number of bagels bought.