How do you find the domain and range and determine whether the relation is a function given {(-2.5,1), (-1,-1), (0,1), (-1,1)}?

Question

Hazel Anglin · Accepted Answer

Domain: #{-2.5, -1, 0}#

Range: #{-1, 1}#

This relation is NOT a function.

The domain is also known as the #x#-values and the range is the #y#-values. Since we know that a coordinate is written in the form #(x, y)#, the #x#-values are: #{-2.5, -1, 0, -1}# However, when we write a domain or range, we typically put the values from least to greatest and do not repeat numbers. Therefore, the domain is: #{-2.5, -1, 0}# All the #y#-values are: #{1, -1, 1, 1}# Again, put them from least to greatest and do not repeat numbers: #{-1, 1}# In a function, each #x#-value can only pair with one #y#-value (each input has a single output). Since there are two #-1#s in the #x#-values pairing with different #y#-values, this relation is NOT a function. I hope this is useful.

Eva Adamson · Answer

undefined Domain: All x-values in the set of ordered pairs: {-2.5, -1, 0}.

Range: All y-values in the set of ordered pairs: {1, -1, 1}.

Determine if it's a function: It is not a function because the x-value -1 is associated with two different y-values (1 and -1).