# Horizontal Line Test

- Author:
- Carlos

A 1 to 1 function is where every x is mapped to a unique value of y, the mathematical term is injective
An onto function is where every y is mapped from at least one x value, mathematical term is surjective.
On the following graph, adjust the values of to move the line and find points of intersection between the line and the function .
1) Is this function 1-1? Explain your answer.
2) Are there any intervals for which is 1-1?
3) Is this function onto? Explain why.

## Graph of f(x)

What about the function below:
1) Is 1-1?
2) Are there any intervals for which is 1-1?
3) Is this function onto? Explain why.

## Graph of g(x)

What features should a graph have in order to represent a 1-1 function? What about an onto function? Test your conjectures by entering a function in the graph below and applying the appropriate tests.