Excerpt from A Treatise on Plane Trigonometry: Containing an Account of Hyperbolic Functions, With Numerous Examples I have given a systematic account of Imaginary Angles and Hyperbolic Functions; the latter, from their great analogy to Circular Functions, are very interesting, and their great and increasing importance, not only in Pure Mathematics but in Mathematical Physics, makes it essen tial that the student should become acquainted with them. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This 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.