A **rational function** is a function that looks like a fraction and has a variable in the denominator.

These functions are rational functions:

The domain of a function consists of the numbers we are allowed to use for the variable in that function. So with rational functions, if there is a number that will cause the denominator of the function to be equal to zero, we need to exclude it from our domain.

Find the domain of f(x)=

We do not want the denominator of this function to ever equal zero.

The only time this would happen is when x=2.

The domain is **"all ***x* not equal to 2".

The range is a bit trickier. In general, you have to graph the function and find the range from the picture.

Determine the domain of the given function:

*To use interval notation*: Write -i to get the symbol

and write i to get the symbol