Two-Point Boundary Value Problems.

In Chapter 1 above we encountered the wave equation in Section 1.4.3 and the heat equation in Section 1.4.4. These equations occur rather frequently in applications, and are therefore often referred to as fundamental equations. We will return to these equations in later chapters. Another fundamental equation is Poisson's equation, given by $$ - \sum\limits_{j = 1}^n {\frac{{\partial ^2 u}} {{\partial x_j^2 }} = f,} $$ where the unknown function u is a function of n spatial variables X1,..., xn. [ABSTRACT FROM AUTHOR]