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# Argument of a function

In mathematics, an argument of a function is a value that must be provided to obtain the function's result. It is also called an independent variable.[1]

For example, the binary function ${\displaystyle f(x,y)=x^{2}+y^{2}}$ has two arguments, ${\displaystyle x}$ and ${\displaystyle y}$, in an ordered pair ${\displaystyle (x,y)}$. The hypergeometric function is an example of a four-argument function. The number of arguments that a function takes is called the arity of the function. A function that takes a single argument as input (such as ${\displaystyle f(x)=x^{2}}$) is called a unary function. A function of two or more variables is considered to have a domain consisting of ordered pairs or tuples of argument values. The argument of a circular function is an angle. The argument of a hyperbolic function is a hyperbolic angle.

A mathematical function has one or more arguments in the form of independent variables designated in the definition, which can also contain parameters. The independent variables are mentioned in the list of arguments that the function takes, whereas the parameters are not. For example, in the logarithmic function ${\displaystyle f(x)=\log _{b}(x)}$, the base ${\displaystyle b}$ is considered a parameter.

The use of the term "argument" in this sense developed from astronomy, which historically used compiled tables to relate the motion of objects to various measured angles. These angles were called arguments, literally "that which elucidates something else."[2][3]

## References

1. ^ Bronshtein, I.N.; Semendyayev, K.A.; Musiol, G.; Muehlig, H. (2007). Handbook of Mathematics (5th ed.). Berlin Heidelberg New York: Springer. p. 47. ISBN 978-3-540-72121-5.
2. ^ Lo Bello, Anthony (2013). Origins of Mathematical Words.
3. ^ Craig, John (1858). A New Universal Etymological, Technological, and Pronouncing Dictionary of the English Language.