A constant is a fixed value that does not change, as opposed to a variable.
Constants can be specific numbers like 5, Ο, or e, or symbolic parameters like c in axΒ² + bx + c. In calculus, constant terms become zero when differentiated. Important mathematical constants include Ο (pi, β 3.14159), e (Euler's number, β 2.71828), Ο (golden ratio, β 1.618), and i (imaginary unit). Physical constants like the speed of light (c) and gravitational constant (G) are constants in scientific equations.
The distinction between constants and variables was formalized by RenΓ© Descartes in the 17th century. Ancient mathematicians used specific constants like Ο and β2. Leonhard Euler introduced the symbols e (1727), i (1777), and Ο (popularized 1736). Mathematical constants have been studied extensively, with some like Ο being computed to trillions of digits.