# Vertical Line Test

- Author:
- Carlos

The vertical line test can be used to determine if the graph of a curve is a function. The vertical line test determines if for every value of x there is only one value of y corresponding to it.
The graph shows the function , and the line . By adjusting the values of , check that passes the vertical line test, i.e. for every value of there is only one value of corresponding to it.

## Graph of h(x)

What about the graph below, does it pass vertical line test?
Is this graph representing a function? Explain why.

Can you think of what features a curve must have to be the graph of a function? Perhaps contrast these two graphs.