Infinity or is a symbol that represents a positive infinite quantity.
can be entered as \[Infinity] or inf.
In StandardForm, Infinity is printed as .
Infinity is converted to DirectedInfinity.
Certain arithmetic operations work with Infinity.
Example: 1/Infinity .
NumberQ[Infinity] yields False.
See The Mathematica Book: Section 1.1.3, Section 2.1.7, Section 3.1.8 and Section 3.2.8.
See also: ComplexInfinity, Indeterminate.