Author Description

Thi8 book is one of a series of text-books to be prepared by the department of mathematics of Cornell University, in accord- ance with the scheme of instruction now in force here. It was outlined and written mainly by Prof. Jones; but it has been carefully read by all of us ; the general plan, and all difficulties, huve been discussed together, the proofs have been submitted to all, and it goes out as our joint production. It is designed as a drill-book for class use ; its leading features are : The general definition of the trigonometric functions in terms applicable to all angles, without regard to sign or magnitude. The expression of the flmctions of all angles in terms of the flinctions of positive angles less than a right angle, by direct reference to the definitions. The graphical representation of functions. The general proof of the formulae for the functions of the sum and difference of two angles, of double angles, half-angles, etc. The differentiation of trigonometric functions, their develop- ment thereby into series, and the computation of the trigono- metric canon by means of these series. The solution of oblique triangles by means of right triangles, as well as by the general properties of triangles ; and by the use of natural as well as logarithmic functions. An exhaustive discussion of the ambiguous and impossible cases of right and oblique triangles. A careful choice and arrangement of topics, according to their relations to practical work and to the higher mathematics. IV PREFACE. The exact statement of principles in the form of theorems and corollaries, and their rigorous demonstration. Frequent reference of collateral matter to the reader for demonstration. Copious and varied exercises. In the preparation of the book, free use has been made of the works of other authors, particularly those of Briot and Bouquet, De Morgan, Todhunter, Peirce, Wheeler, Greenleaf, Loomis, and Chauvenet. The careful reader will doubtless find many t^'pographical and o