For by finding out that in this calculus the linear relation is obtained through the first function of the equation, we also know that the integration of this relation yields the equation of the curve in the relation of abscissa and ordinate; or, if the equation for the area enclosed by the curve were given, then, regarding the meaning of the first function of this equation, we should have already learned from differential calculus that such a function displays the ordinate as a function of the abscissa, and therefore the equation of the curve.