THE ELEMENTS

OF

PLANE AND SPHERICAL

TRIGONOMETRY.

BY

EUGENE L. RICHARDS, B. A.,

ASSISTANT PROFESSOR OF MATHEMATICS IN YALE COLLEGE.

NEW YORK:

D. APPLETON AND COMPANY,

549 AND 551 BROADWAY.

1879.

Educ T168.79.735

HARM

MISS ELLEI L. WENTWORTH

SEP 13 1941

COPYRIGHT BY

D. APPLETON AND COMPANY.

1879.

PREFACE.

IN the following pages the author has aimed to make the subject of Trigonometry plain to beginners, and has, therefore, devoted a great deal of space to the elementary definitions and to the application of them.

Spherical Trigonometry is a subject so difficult to grasp, that any treatise on it designed for beginners should, in the opinion of the writer, make frequent use of diagrams, to convey to the student a clear idea of the relations of the magnitudes under treatment. Consequently, this kind of illustration has been applied wherever it could be of any possible assistance.

The references are to "Todhunter's Euclid" and to "Chauvenet's Geometry."

The answers to examples have been obtained by means of six-place tables.