# How do you use the vertical line test to show #sqrt(x^2-4)-y=0# is a function?

##### 1 Answer

#### Answer:

intersects with a vertical line only once

#### Explanation:

first, rearrange the function so that

the graph should look like this:

graph{sqrt(x^2-4) [-10, 10, -5, 5]}

then, pick any number outside the range

example:

this is a vertical line, all points on which have an

in the vertical line test, a graph is shown to be a function if it meets a given vertical line only once.

the image above shows that the graph

(the vertical line test can be done again with other