Chinese Name: Infinite Symbol

Mbth: ∞

First use time: 1655 years

First time user: Wallis

Mathematical operation:

When describing an interval, only the upper bound is (-∞, x] (x ∈ r); Only the lower bound is [x, +∞) (x ∈ r); If there is neither upper limit nor lower limit, it is (-∞,+∞).

In advanced mathematics, it is stipulated that x is a real number, when x >；; 0，x÷0 =+∞； When x

Addition, subtraction, multiplication, division, multiplication and root operations of +∞ and real numbers always result in +∞; The addition, subtraction, multiplication, division, multiplication and root operation of-∞ and real numbers always result in-∞. (0 ×∞ meaningless)