**Functions and parametric surfaces**

Visualizing *z* = *f*(*x*, *y*), or, with polar coordinates, *z* = *f*(*r*, *&theta*).
You can specify any function of *x* and *y* (or, in the case of polar coordinates,
of *r* and *&theta*, writing *&theta* as *t*). Parametric surfaces are based on three unit vectors **i**, **j** and **k** in the directions of the x-, y and z-axes, respectively.
You can use

Cartesian coordinates

*x*and*y*, polar coordinates*r*and*t*(=*&theta*) or surface parameters*u*and*v*. In the latter case you should also use the unit vectors**i**,**j**and**k**, in that order.numerical constants such as

`-0.1`the functions

`abs`,`acos`,`asin`,`atan`,`ceil`,`cos`,`cosh`,`exp`,`floor`,`log`,`max`,`min`,`round`,`sgn`,`sin`,`sinh`,`sqrt`,`tan`,`tanh`, and the constants*&pi*(written as*pi*) and*e*the operators

`+ - * / ^`parentheses ( ), { }, [ ]

This applet was written by Leen Ammeraal and is related to Java programs discussed in
Computer Graphics for Java Programmers, 2nd Edition, by Ammeraal and Zhang.