Functions of two variables can be visualized in many ways: heat maps in 2D, contour curves in 2D, wireframes in 3D, surfaces in 3D. We begin by defining a function of two variables, building an array ...

In this code, the inc function uses the global keyword to access the $a variable declared at the top level. When it sets $a, ...

vector-valued functions and functions of two or more variables. Topics include convergence of power series, partial derivatives, double and triple integrals with applications to surface area and ...