Domain and Range of Functions

In these lessons, we will learn how to find the domain and range of functions.

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The following diagrams show the domain and range of a function. Scroll down the page for more examples and solutions.

Domain Range

Domain and Range

How to find the domain and range?

An important part of understanding functions is understanding their domain and range. Domain and range are all the possible x-values and y-values of the function, and can often be described easily by looking at a graph. In order to grasp domain and range, students must understand how to determine if a relation is a function and interpreting graphs.

This video provides two examples of how to determine the domain and range of a function given as a graph.

Examples of how to determine the domain and range of a function given as a graph

How to Find the Domain & Range of a Function

Finding the domain and range of a function is as simple as finding the possible X and Y values, respectively.
Learn about X and Y values as dependent and independent variables.

Finding the Domain of a Function Algebraically

Finding the domain of a function, without graphing.


  1. No zero in the denominator of a fraction.
  2. No negative numbers under square roots after simplifying.

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