FUNCTION

FUNCTION, the act of fulfilling the duties of any employment.

FUNCTION is a term used in analytics for an algebraical expression in any way compounded of a certain letter or quantity with other quantities or numbers; and the expression is said to be a function of that letter or quantity.

Thus $a\; -\; 4x$, or $ax\; +\; 3x^2$, or $2x\; -\; a\backslash sqrt\{a^2\; -\; x^2\}$, or $x^5$, or $e^x$, is each of them a function of the quantity $x$.