Question

Explain why the vertical line test is used to determine if a graph represents a function.

Answer 1

A relation is considered a function if every x-value maps to at most one y-value. For example, the equation y = sin(x) is a function, but x^2 + y^2 = 1 is not, since a vertical line at x equals, say, 0, would pass through two of the points. For a relation to be a function, any vertical line drawn must not cross more than one point on the domain/range.

Answer 2

A function, f(x) must have only one value. A line x=a must only cut the curve once for all 'a' over the domain, otherwise it is not a function

Answer 3

becasue its so easy to write out every single point of a graph from infinity to infinity and draw a vertical line thru all the Real values on x to see if it only hits at one point ....