Excerpt from A Treatise on Plane and Spherical Trigonometry: Including the Construction of the Auxiliary Tables; A Concise Tract on the Conic Sections, and the Principles of Spherical Projection Constant quantities are such as remain unchanged, or retain the same value throughout the investigation. Variable quantities are those which change their value inthe course of the solution or demonstration. Constant quantities are usually denoted by the initial letters, a, b, c, &c.; variable ones by the final letters, ac, y, z, &c. 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.