Absolute value - Wikipedia
https://en.wikipedia.org/wiki/Absolute_valueThe real absolute value function is continuous everywhere. It is differentiable everywhere except for x = 0. It is monotonically decreasing on the interval (−∞, 0] and monotonically increasing on the interval [0, +∞). Since a real number and its opposite have the same absolute value, it is an even function, and is hence not invertible. The real absolute value function is a piecewise linear, convex function.
Absolute Value Functions - Varsity Tutors
www.varsitytutors.com › absolute-value-functionsAn absolute value function is a function that contains an algebraic expression within absolute value symbols. Recall that the absolute value of a number is its distance from 0 on the number line. The absolute value parent function, written as f (x) = | x |, is defined as . f (x) = {x if x > 0 0 if x = 0 − x if x < 0. To graph an absolute value function, choose several values of x and find some ordered pairs.