Excerpt from Plane and Spherical TrigonometryThis text-book in Trigonometry aims to develop in the student the ability to think out and apply the relations between the trigonometric functions. The definition of the functions by means of projection is not only based on a conception familiar from Geometry, but is also the key to many of the applications of the functions.Tables of functions are not included in the book, as it is thought better that the student use separate tables.The student should learn from the start that Trigonometry demands reasoning, not memorizing.Teachers are beginning to recognize that it is more profitable for students to check computations, either by means of a check formula or by comparing the results of independent work than to rest content with a result that agrees with a printed answer. For this reason answers are as a rule omitted in this text.About the PublisherForgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.comThis book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully, any imperfections that remain are intentionally left to preserve the state of such historical works.