Graphical Behavior

Domain

The domain of a rational function is all real numbers, excluding values that lead to a zero in the denominator. These values have been presented as excluded values or points of discontinuity.

Example 1 Describe the Domain.

frac1

Step 1. Factor the denominator.

equation1

equation2

Step 2. Using Zero Product Property set each factor equal to zero and solve.

equation3 or equation5

equation6 or equation7


Step 3. The domain will be all real numbers excluding the value(s) from step 2.

The domain is: all real numbers excluding x = 3, x = -3.

This can be written in set notation as: set1