William Frend on Simon Stevin

“The chapter of this valuable book... (...which I had reprinted... as an Appendix to Mr. Frend's Principles of Algebra,) relates to the method invented by Simon Stevinus... for finding... the first near value of x, or the root of any proposed Algebräick equation, by repeated conjectures and trials with easy numbers of one or two decimal figures: after having found which we may proceed to determine the value of the said root to a greater degree of exactness by one or more applications of Mr. Raphson's method of approximation. The title of this 10th Chapter of Mr. Kersey's Algebra is as follows: An Explanation of Simon Stevin's General Rule to extract one Root out of any possible Equation of Numbers, either exactly or very nearly true.”

“I shall lead the industrious learner a few steps farther in order to his understanding the resolution of all manner of compound equations in numbers, and... shall explain Simon Stevin's General Rule, which, with the help of the rules in the following eleventh Chapter, will discover all the roots of any possible equation in numbers, either exactly, if they be rational, or very nearly true, if irrational.”