Domain- The domain of a relation is the set of all possible values that can be used for the input of the independent variable (x).
Range- The range of a relation is the set of all possible values of the output of the dependent variable (y).
How to find domain
![Graph of a function from (-3, 1].](https://s3-us-west-2.amazonaws.com/courses-images/wp-content/uploads/sites/896/2016/10/18193551/CNX_Precalc_Figure_01_02_0072.jpg)
Step 1: Identify the domain of the relation. Which is along the x axis.
Step 2: The domain of the relation starts at -3 and ends at 1.
Step 3: Write the domain as follows: -3 < x ≤ 1
Step 4: This shows all the possible values that can be used for the input.
How to find range
Step 1: Identify the range of the relation. Which is along the y axis.
Step 2: The range of the relation starts at -4 and ends at 0.
Step 3: Write the range as follows: -4 ≤ x ≤ 0.
Step 4: This shows all the possible values that can be used for the output.
Why
Range and domain is used in real life to make mathematical calculations. For an example, range can be used to calculate the amount of time that has passed and we can take a function that represents real world situations and then analyze what the domain and range represent in the function. Domain and range are important values to help define a relation.
Sources
Learning, Lumen. “College Algebra.” Lumen, https://courses.lumenlearning.com/waymakercollegealgebra/chapter/find-domain-and-range-from-a-graph/.