Main subject categories: • Linear Partial Differential Equations • Differential Equations • Mathematical Models • Linear Equation Classification • Cauchy Problem • Wave Equations • Fourier Series • Method of Separation of Variables • Eigenvalue Problems • Special Functions • Boundary-Value Problems • Higher-Dimensional Boundary-Value Problems • Green's Functions • Integral Transform Methods • Engineering Mathematics • Mathematical PhysicsThis significantly expanded fourth edition is designed as an introduction to the theory and applications of linear PDEs. The authors provide fundamental concepts, underlying principles, a wide range of applications, and various methods of solutions to PDEs. In addition to essential standard material on the subject, the book contains new material that is not usually covered in similar texts and reference books. It also contains a large number of worked examples and exercises dealing with problems in fluid mechanics, gas dynamics, optics, plasma physics, elasticity, biology, and chemistry; solutions are provided.