MATH0 STAT. Edward Bright Mathematics Dept r A COURSE OF PURE MATHEMATICS CAMBRIDGE UNIVERSITY PRESS C. F. CLAY, MANAGER LONDON : FETTER LANE, E.G. 4 NEW YORK THE MACMILLAN CO. : BOMBAY \ CALCUTTA LMACMILLANANDCO.,LTD. MADRAS TORONTO J THE MACMILLAN CO. OF : CANADA, LTD. TOKYO MARUZEN-KABUSHIKI-KAISHA : ALL RIGHTS RESERVED A COURSE OF PURE MATHEMATICS ) BY G. H. HARDY, M.A., F.R.S. FELLOW OF NEW COLLEGE SAVILIAN PROFESSOR OF GEOMETRY IN THE UNIVERSITY OF OXFORD LATE FELLOW OF TRINITY COLLEGE, CAMBRIDGE THIRD EDITION Cambridge at the University Press 1921 VU First Edition 1908 Second Edition 1914 Edition 1921