ON HIGHER TRIGONOMETRY. BY THE REV. J. B. LOCK, M.A. SENIOR FELLOW, ASSISTANT TUTOR AND LECTURER IN MATHEMATICS OF London: MACMILLAN AND CO. 1884 [All Rights reserved.] PREFACE. THE present work is intended to complete the subject of Plane Trigonometry as far as it is usually read in Schools and in the junior Classes at the Universities. The introduction of the hyperbolic sine and cosine is an innovation which seems fully justified by their importance in other subjects, and by the simplification effected by their use in the statement of many theorems and formulæ. I wish to thank the Master of Gonville and Caius College for his valuable advice and assistance and for his permission to insert the proof given in Art. 62. The method of proof employed in Art. 47 was first suggested by Professor Adams. I shall be very grateful for any suggestions or corrections from teachers or students. J. B. L. ETON, March, 1884. |