Mathwords: Horizontal Line Test. A test use to determine if a function is one-to-one. If a horizontal line intersects a function's graph more than once, then the function is not one-to-one. Note: The function y = f(x) is a function if it passes the vertical line test.
A horizontal line test is used to determine if a function is one to one. If the line intersects a functions graph more than one then the function is not one to one.
Step-by-step explanation:
The function y=f(x) is a function if it passes the vertical line test.
