Open Point
1. Let's clarify the problem: An open point on a graph means the point is not included in the function's domain or range at that coordinate.
2. For example, if a function has a hole at $x=a$, it means $f(a)$ is undefined or not part of the function.
3. The function might approach a value near $x=a$, but the point $(a, f(a))$ is not included.
4. This is often represented graphically by a circle that is not filled in at that point.
5. Mathematically, if $\lim_{x \to a} f(x) = L$ but $f(a)$ is undefined or different from $L$, then there is an open point at $x=a$.
6. Open points indicate discontinuities or removable discontinuities in the function.
7. Understanding open points helps in analyzing limits and continuity of functions.