GEOMETRY AND TRIGONOMETRY; WITH 6. Shi PRACTICAL APPLICATIONS. BY BENJAMIN GREENLEAF, A. M., AUTHOR OF A MATHEMATICAL SERIES. IMPROVED ELECTROTYPE EDITION. BOSTON: PHILADELPHIA: J. B. LIPPINCOTT AND COMPANY. “ 18 6 2. PUBLIC LIBRARY 864722 A RE EN LEAF'S 1936 L Greenleaf's New Primary Arithmetic, Greenleaf's Intellectual Arithmetic, Greenleaf's Common School Arithmetic, Greenleaf's National Arithmetic, Academies, and Normal Schools. New Electrotype Edition, with Greenleaf's Treatise on Algebra, Greenleaf's Geometry and Trigonometry, and Colleges. Improved Electrotype Edition. 490 pp. Complete Keys to the Intellectual, Common School, and National Entered according to Act of Congress, in the year 1858, by BENJAMIN GREENLEAF, Entered according to Act of Congress, in the year 1861, by BENJAMIN GREENLEAF, Cambridge : Electrotyped and Printed by Welch, Bigelow, & Co. PREFACE. s. The preparation of this treatise was undertaken at the earXinest solicitation of many teachers, who, having used the author's Arithmetics and Algebra with satisfaction, were desirous of seeing his series rendered more nearly complete by the addition of the Elements of Geometry and Trigonometry. That there are peculiar advantages in a graded series of textbooks on the same subject, few, if any, properly qualified to judge, will doubt. The author, therefore, feels justified in introducing this volume to the attention of the public. In the Elements of Geometry, he has followed, in the main, the simple and elegant order of arrangement adopted by Legendre; but in the methods of demonstration no particular authority has been closely followed, the aim having been to adapt the work fully to the latest and most approved modes of instruction. In this respect, there will be found incorporated a considerable number of important improvements. . More attention than is usual in elementary works of this kind has been given to the converse of propositions. In almost all cases where it was possible, the converse of a proposition has been demonstrated. The demonstration of Proposition XX. of the first book is essentially the one given by M. da Cunha in the Principes Mathématiques, which has justly been pronounced by the highest mathematical authorities to be a very important improvement in elementary geometry. It has, however, never before been introduced into a text-book by an American author. |