In doing this he makes use of a Table of Products (...he calls Speculum Analyticum,) by which he computes the Coefficients in the new Equation for fi… - Brook Taylor

Considering how few, and how simple the Principles are, upon which the whole Art of <small>PERSPECTIVE</small> depends, and withal how useful, nay how absolutely necessary this Art is to all forts of Designing; I have often wonder'd, that it has still been left in so low a degree of Perfection, as it is found to be, in the Books that have been hitherto wrote upon it.

<math>z</math> and <math>x</math> being two flowing Quantities (whose Relation... may be exprest by any Equation...) by [the aforesaid] Corollary, while <math>z</math> by flowing uniformly becomes <math>z+v</math>, <math>x</math> will become<math>x + \frac {\dot{x}}{1 \cdot \dot{z}}v + \frac {\ddot{x}}{1 \cdot 2 \cdot \dot{z}^2}v^2 +</math>... etc. or

Hence if <math>y</math> be the Root of any Expression formed of <math>y</math> and known Quantities, and supposed equal to nothing, and <math>z</math> be a part of <math>y</math>, and <math>x</math> be formed of <math>z</math> and the known Quantities, in the same manner as the Expression made equal to nothing is formed of <math>y</math>; and let <math>y</math> be equal to <math>z + v</math>; the difference <math>v</math> will be found by Extracting the Root of this expression <math>x + \frac {\dot{x}v}{1} + \frac {\ddot{x} v^2}{1 \cdot 2} + </math> ... etc. <math>= 0</math>.