One-Sided Limit
Left Sided Limit or Left Hand Limit
Right Sided Limit or Right Hand Limit
The limit of a function at a point if it exists, is unique.
In this case, it can be seen that the limit from both the left and right sided as x tends to 2 is 4.
The limit of the function is 4 as x tends to 2 even though the function has no value at x = 2.
To calculate the limit of a function at a point, it is not of importance what happens at that particular point, but what happens around it.
Example
Given the function:
Calculate 
.
The function has no limit at x = 0.
