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The notation | x |, with a vertical bar on each side, was introduced by Karl Weierstrass in 1841. [5] Other names for absolute value include numerical value [1] and magnitude. [1] In programming languages and computational software packages, the absolute value of is generally represented by abs(x), or a similar expression.
The expected values of the powers of X are called the moments of X; the moments about the mean of X are expected values of powers of X − E[X]. The moments of some random variables can be used to specify their distributions, via their moment generating functions.
4. Mean value: If x is a variable that takes its values in some sequence of numbers S, then ¯ may denote the mean of the elements of S. 5. Negation: Sometimes used to denote negation of the entire expression under the bar, particularly when dealing with Boolean algebra.
Signum function = . In mathematics, the sign function or signum function (from signum, Latin for "sign") is a function that has the value −1, +1 or 0 according to whether the sign of a given real number is positive or negative, or the given number is itself zero.
The value of a function, given the value(s) assigned to its argument(s), is the quantity assumed by the function for these argument values. [1] [2] For example, if the function f is defined by f (x) = 2 x 2 – 3 x + 1, then assigning the value 3 to its argument x yields the function value 10, since f (3) = 2·3 2 – 3·3 + 1 = 10.
In mathematics, x is commonly used as the name for an independent variable or unknown value. The modern tradition of using x, y, and z to represent an unknown was introduced by René Descartes in La Géométrie (1637). [8]
A mathematical constant is a key number whose value is fixed by an unambiguous definition, often referred to by a symbol (e.g., an alphabet letter), or by mathematicians' names to facilitate using it across multiple mathematical problems. [1]
More precisely, if : is a real-valued function (or, more generally, a function taking values in some additive group), its zero set is (), the inverse image of {} in . Under the same hypothesis on the codomain of the function, a level set of a function f {\displaystyle f} is the zero set of the function f − c {\displaystyle f-c} for some c ...