Using the vertical line test to determine if a graph is a function or not

The video tutorial explains the concept of functions, emphasizing that each input has exactly one output. It discusses the domain of functions and introduces the vertical line test as a method to determine if a graph represents a function. The tutorial provides examples of graphs that pass and fail the vertical line test, highlighting the importance of having only one output for each input. The video concludes with a summary of the vertical line test's simplicity and effectiveness.

What happens when a vertical line crosses a graph more than once?

Why is the vertical line test considered a simple method for identifying functions?