Extended Real Number Line

The extended real number system is formed from the ordinary real numbers by adding two elements, positive infinity and negative infinity, defined to be greater or lower respectively than every real number. This lets an infinitely increasing sequence, such as the natural numbers, have an actual limit and least upper bound rather than merely growing without bound, and it significantly extends what can be computed in calculus and mathematical analysis when infinite limits are treated as actual values. The extended real number line is distinct from the projectively extended real line, a related construction in which positive and negative infinity are identified as a single point rather than kept separate. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/