Graphs That Are Not Functions Of X. Does the line touch two or more points on the graph. If the vertical line hit the graph twice the x value would be mapped to two y values and so the graph would not represent a function.
Recall that if f is a polynomial function the values of x for which latex f left x right 0 latex are called zeros of f if the equation of the polynomial function can be factored we can set each factor equal to zero and solve for the zeros. This curve fails the vertical line test. This leads us to the vertical line test.
If any vertical line intersects the graph in more than one point the graph does not represent a function.
Then it is not a function of y. This curve fails the vertical line test. For other functions the values f x may not approach a finite number but instead may become larger for all values of x as they get larger. Students will calculate too small a set of point to graph a function.
