This highly visual introductory textbook presents an in-depth treatment suitable for undergraduates in mathematics and physics, gradually introducing abstraction while always keeping the link to physical motivation. Designed for lecturers as well as students, downloadable files for all figures, exercises, and practice problems are available online, as are solutions. Это и многое другое вы найдете в книге Linear Partial Differential Equations and Fourier Theory (Marcus Pivato)