In mathematics, a unary operation is an operation with only one operand, i.e. a single input.
[1] This is in contrast to binary operations, which use two operands.
Other notations exist as well, for example, in the case of the square root, a horizontal bar extending the square root sign over the argument can indicate the extent of the argument.
Obtaining the absolute value of a number is a unary operation.
Here are some examples: For any positive integer n, the product of the integers less than or equal to n is a unary operation called factorial.
In the context of complex numbers, the gamma function is a unary operation extension of factorial.
In trigonometry, the trigonometric functions, such as
This is because it is possible to provide only one term as input for these functions and retrieve a result.
By contrast, binary operations, such as addition, require two different terms to compute a result.
Below is a table summarizing common unary operators along with their symbols, description, and examples:[3] In JavaScript, these operators are unary:[4] In the C family of languages, the following operators are unary:[5][6] In the Unix shell (Bash/Bourne Shell), e.g., the following operators are unary:[7][8] In the PowerShell, the following operators are unary:[9]