A partial differential equation (PDE) relates the quantities of a multivariate function and its various partial derivatives in an equation. An ordinary partial differential, as discussed in the previous chapter, is a subclass of partial differential equations because ordinary partial differential equations deal with functions with one variable. Partial differential equations are significantly more difficult to solve than ordinary partial differentials because a simple PDE can admit a large class of solutions. For example, for this simple PDE,
any function v(x, y) = f(x) +
