ξ Chinese transliteration, Cauchy, is the14th letter of the Greek alphabet, lowercase ξ is used for random variables in mathematics, and uppercase ξ is used for baryons in particle physics. Greek letters and their meanings: 1.α, lowercase α, Chinese transliteration, α.

Communication:

182 1 year, Cauchy (France, 1789- 1857) gave a definition from the definition of variables: "Some variables have certain relationships. When the value of one variable is given, the values of other variables can be determined accordingly, so the initial variable is called independent variable.

The word independent variable appeared for the first time in Cauchy's definition, and pointed out that functions don't need analytic expressions. However, he still believes that functional relationships can be expressed by multiple analytical expressions, which is a great limitation.