When working with limits. what difference does it make if theres an open circle and closed circle?
An open circle (also called a removable discontinuity) represents a hole in a function, which is one specific value of x that does not have a value of f(x).
With limits, the limit exists as long as the limit from the left is equal to the limit from the right. So, if a function approaches the same value from both the positive and the negative side and there is a hole in the function at that value, the limit still exists.
However, if a function has a hole at a certain value, it is not continuous across that value.