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)}?

1 Answer
Aug 2, 2018

Answer:

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

Range: #{-1, 1}#

This relation is NOT a function.

Explanation:

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.

Hope this helps!