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Mathematics vocabulary · Functions and Graphs

Function

Meaning in mathematics, with examples

/ˈfʌŋkʃən/nounCore term

In mathematics, function means: A rule that takes each input from a set and gives exactly one output, for example f(x) = 2x + 1, which doubles a number and adds one.

In Turkish: fonksiyon, işlev

How it is used

One of the most used words from school to university. You define, evaluate, graph and differentiate a function. People say 'y is a function of x' and talk about linear, quadratic, exponential and trigonometric functions.

Example sentences

  1. Evaluate the function at x = 3 and plot the point.

  2. Is this graph a function? Check whether any vertical line crosses it twice.

Common collocations

  • define a function
  • evaluate a function
  • linear function
  • a function of x
  • graph of a function
  • f of xThe usual spoken form of f(x), the output of a function f when the input is x; for example, if f(x) = x + 5, then 'f of 2' is 7.
  • domainThe set of all input values for which a function is defined; for f(x) = 1/x, the domain is all real numbers except 0.
  • graphA drawing that shows the relationship between quantities, especially all the points (x, y) of a function shown on a pair of axes.
  • inverse functionA function that reverses the effect of another function, so that if f(2) = 7, the inverse of f takes 7 back to 2.
  • variableA letter or symbol, such as x or y, that stands for a number which can change or which you do not know yet.

This word in other fields

The same English word can have a different meaning in another field:

More terms: Functions and Graphs

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