Math Dictionary / Domain and Range

Domain and Range

The domain is the set of possible inputs of a relation or function; the range is the set of possible outputs.

FunctionsGrade 8Algebra 1Algebra 2SATACT

What it means

Domain asks what x-values can go in. Range asks what y-values can come out.

Also called: inputs and outputs

Examples

For points (1, 4), (2, 5), domain = {1, 2}
Range = {4, 5}
For y = x^2, the range is y >= 0

Common mistake

Do not swap them: domain goes with inputs, range goes with outputs.

Try one

Question: For points (2, 7), (3, 7), (5, 9), what is the domain?

Show answer

The domain is {2, 3, 5}.

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