Welcome to Many Variable Calculus (Core B). Many functions in the real world depend on more than one variable and the basic idea of this course is to teach how to the ideas of differentiation and integration extend to such functions. When we have more than one variable ordinary differentiation is replaced by partial differention, and ordinary differential equations become partial differential equations. Wave motion is one of many phenomena described by partial differentia equations; the example studied here is vibration of a stretched string, such as a guitar string. Fourier series, which are also introduced in this course, provide a useful tool for solving wave motion. I hope to post problem sheets, solutions (eventually!) and handouts on these webpages as well as providing some links to other sites with some interesting and relevant material