# Variable - Characteristics Of A Variable, Variables In A Function

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represent mathematical modern letters

A variable is a mathematical symbol which is used to represent a member of a given set and is typically denoted by a letter such as x, y, or z. The idea of a variable, invented during the late sixteenth century, is characteristic of modern **mathematics** and was not widely used in ancient times. Since a variable reflects a quantity which can take on different values, its use has become a critical part of nearly all disciplines which use mathematical models to represent the real world.

The idea of using letters to represent variables was first suggested by the sixteenth century mathematician François Viète (1540-1603) in his work, *In artem analyticam isagoge* (1591). Although his notations barely resemble our modern day symbolism, they were an important step in the development of the concept of using a letter to represent a changing value in a mathematical equation. His ideas were further developed in the decades that followed. Rene Descartes (1596-1650) is generally credited for making standard, the use of the letters x, y, and z for variables.

## Additional Topics

A variable is often denoted by a letter in an algebraic expression and represents a value which can be changed or varied. For example, in the expression x + 2, the letter x is a real variable and can take on the value of any real number. If x is 4 then the expression has a value of 6 because 4 + 2 = 6. Similarly, if x is 10 the expression has a value of 12. The number 2 in this expression is known…

Some algebraic equations, known as functions, represent relationships between two variables. In these functions, the value of one variable is said to depend on the value of the other. For instance, the sales tax on a pair of gym shoes depends on the price of the shoes. The distance a car travels in a given time depends on its speed. In these examples, the sales tax and the distance travelled are c…

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## User Comments

over 3 years ago

Alyssa Gomez

Next time make a simple definition and a long one. That includes the characteristics too ;) I love u!!!!

over 2 years ago

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