Page 38 - Basics of MATLAB and Beyond

We can plot the surface z as a function of x and y:

mesh(x,y,z)

We can expand the domain of the calculation by increasing the input
to meshgrid. Be careful to end the lines with a semicolon to avoid being
swamped with numbers:

[x,y] = meshgrid(-10:10);
z = sqrt(x.^2 + y.^2);
mesh(x,y,z)

The surface is an inverted cone, with its apex at (0, 0, 0).
Companion M-Files Feature 3 A clearer plot can be produced
using a polar grid, instead of a rectilinear grid. We can use the
companion function polarmesh to produce such a plot. First we
define a polar grid of points:

[r,th] = meshgrid(0:.5:10,0:pi/20:2*pi);
Then display the surface defined by z = r:

polarmesh(r,th,r)

A more interesting surface is
2
2 −x −(y+1)
1
3
5
z = 3(1 − x) e 2 2 − 10( x − x − y )e −x −y 2 ···
5
1 −(x+1) −y
− e 2 2 .
3
In matlab notation you could type:
c 2000 by CRC Press LLC