Question

what is sigmum? Define ​

Answer 1

Answer:

Sign function -

In mathematics, the sign function or signum function (from signum, Latin for "sign") is an odd mathematical function that extracts the sign of a real number. In mathematical expressions the sign function is often represented as sgn.

Answer 2

The sign of a real number, also called sgn or signum, is -1 for a negative number (i.e., one with a minus sign "), 0 for the number zero, or +1 for a positive number (i.e., one with a plus sign"). In other words, for any real x