Unary operation

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In mathematics, a unary operation is an operation with only one operand, i.e. an operation with a single input, or in other words, a function of one variable (for the terminology see also operators versus functions).

Common notations are prefix notation (+, -, not), postfix notation (factorial: n!), and functional notation (sin x or sin (x)). In the case of the square root a horizontal bar over the argument extending the square root sign can indicate the extent of the argument, so that parentheses can be dispensed with.

[edit] Examples of Unary Operations

  • the absolute value operation is a unary operation on the real numbers
  • the opposite operation (-x) on the real numbers
  • the power operation (squaring, cubing, etc) on the real numbers
  • the factorial operation on the real numbers
  • the trigonometric operations (sin x, cos x, tan x, cot x, csc x) on the real numbers
  • the natural logarithm (ln x) on the real numbers
  • the logarithm of base 10 (log x) on the real numbers
  • logical negation on truth values
  • A unary operation on a given set S is nothing but a function SS, also called an endomorphism of S.


[edit] Computer Programming

Unary operators (called "monadic" in APL) are also used in programming languages. For example, in the C family of languages, the following operators are unary:

[edit] See also