# Calculus A general diagram of "calculus" of a moving point in a Cartesian system in time (Newton, 1666). 
In mathematics, calculus, from the Latin calcis- “small stone”, as in infinitesimal counting, refers to the method of mapping the motion of a moving point in time, on a two-dimensional Cartesian coordinate system, originally developed by Roberval (c.1635) (Ѻ), such that the curve, defined by the function f(x,y) = 0, is regarded as the locus of the intersection of two moving lines, one horizontal motion (x-axis) the other vertical motion (y-axis), whereby the “derivative” (see: differential calculus) of each motion, in respect to time, is the velocity in each respective direction, according to which the tangent of the curve is the velocity of the particle; the “integration” (see: integral calculus) of the function of the curve yields the area under the curve (Newton, 1666).

References
1. (a) Newton, Isaac. (1666). “Tract on Fluxions”, Oct.
(b) Edwards, C.H. (1975). The Historical Origin of Calculus (§: Calculus According to Newton, pg. 191-92). Springer.