Removable Discontinuity
A discontinuity is removable at a point x = a if the 
exists and this limit is finite.
There are two types of removable discontinuities:
1. The function is undefined at x = a.
2. The value of the function at x = a does not match the limit.
When a function has a removable discontinuity, it can be redefined to make it a continuous function.
The two functions previously studied can be redefined such that:
