1. Absolute value of a number
a.v. of a positive number or zero is the number itself,
a. v. of a negative number is the opposite number;
in other words: it is a distance from zero to the given number on the number line.
2. Absolute value of a vector
The length/magnitude/norm of this vector.
3. Absolute value function
Notacja:
1. |a|, abs(a)
2. |$\vec{a}$|, ||$\vec{a}$||
3. y = |x|, y = abs(x)
read it: y equals the absolute value of x