The Parameter Equation in 3D
A surface is given by a parameter equation if the x-, y- and z-coordinates of the points of the surface can be expressed in terms of two real parameters u and v, as illustrated below.
For the parameters u and v, one always has to enter a range. Here, you can find for example the graph of the surface with parameter equation
x(u,v) = (2+cos(u))*cos(v), y(u,v) = (2+cos(u))*sin(v) and z(u,v) = sin(u),
for the parameters u and v between 0 and 2*pi.
