The sign function, denoted by f(x) = -x, is a fundamental mathematical concept.

This function calculates the sign of a number. The sign determines the value of the result.

For example, f(5) = -5, f(-5) = 5, f(0) = 0, f(10) = -10, and so on.

This function is often used in computer graphics, signal processing, and various other applications.

It's a foundational concept in many mathematical and scientific disciplines.