PIAGGIO, H. T. H. — AN ELEMENTARY TREATISE ON DIFFERENTIAL EQUATIONS AND THEIR APPLICATIONS

LONDON : G. BELL AND SONS 1944 Revised and Enlarged Edition 1922 reprinted 1944 XV +256 + XXVII p., tables, formulas, answers to exercises, index HARDCOVER: Orig. publishers blue cloth. Spine bit faded. Corners bit bumped. Two small stamps R.A.F. library Pencil name end paper,else GOOD ) VERY RARE (war) EDITION. PREFACE The Theory of Differential Equations, said Sophus Lie, is the most important branch of modern mathematics. The subject may be considered to occupy a central position from which different lines of development extend in many directions. If we travel along the purely analytical path, we are soon led to discuss Infinite Series, Existence Theorems and the Theory of Functions. Another leads us to the Differential Geometry of Curves and Surfaces. Between the two lies the path first discovered by Lie, leading to continuous groups of transformation and their geometrical interpretation. Diverging in another direction, we are led to the study of mechanical and electrical vibrations of all kinds and the important phenomenon of resonance. Certain partial differential equations form the starting point for the study of the conduction of heat, the transmission of electric waves, and many other branches of physics. Physical Chemistry, with its law of mass-action, is largely concerned with certain differential equations.