Casio Reckon User Manual page 9

It is also possible to plot 3D surfaces, using the Plot3D function (F3). Two independent variables are
required, notionally X and Y. The range of X and Y may be supplied as parameters.
Example:
Plot3D(X^2-Y^2,-2,2,-2,2)
Quite often the range of X and Y is the same, so it is sometime easier to supply just one range, eg:
Plot3D(X^2-Y^2,-2,2)
By default Plot3D chooses a grid of 10x10 samples. It' s possible to change this by adding the sample mesh
density as an additional parameter. However, increasing the number does not always produce clearer
results. Indeed 16 is about maximum, otherwise there is no memory left! eg.
Plot3D(X^2-Y^2,-2,2,14)
When the 3D surface is displayed, a number of control keys alter the view
Key
Direction pad
+
-
AC
8, 5
7, 4
9,6
0
Purpose
Pan side to side and up and down
Zoom In
Zoom Out
Quit
Rotate parallel to the Z axis centred on view
Rotate parallel to the X axis centred on view
Rotate parallel to the Y axis centred on view
Reset the view