Gustafson K.E. Introduction to Partial Differential Equations and Hilbert Space Methods

Dover, 1997. - 476 pages. ISBN: 0486612716Excellent undergraduate/graduate-level introduction presents full introduction to the subject and to the Fourier series as related to applied mathematics, considers principal method of solving partial differential equations, examines 1st-order systems, computation methods, and much more.
Over 600 problems and exercises, with answers for many. Ideal for a 1-semester or full-year course.