HP 48g Graphing Calculator - Manual (Page 296)

Understanding the PLOT Reserved Variables
The PLOT application makes it easy to declare the plot and display
ranges, the scale and resolution of the plots, and various other
characteristics of the plot.
All of the information about a plot is automatically stored in a small
set of r e s e r v e d v a r i a b l e s that
3 'ou have direct access to if you wish.
Because they are variables, stored in directories, you can have a
different version of these reserved variables in every directory.
22
EQ
E Q contains the current equation or the name of the variable
containing the current equation.
Specifically, the “equation” that E Q contains can be any of the
following for the PLOT application:
■ A single algebraic object or a name containing a single algebraic.
■ A real number (or a complex number for the Parametric plot type)
or a name containing a real number.
B A program that takes nothing from the stack and yields exactly one
real (or complex for the Parametric plot type) result or a name
containing such a program.
■ A list containing any combination of the preceding three possibilities
or the name of such a list. Although all elements are plotted, the
first element of the list is always considered to be the “current”
equation.
SDAT
E D A T contains the current statistical matrix or the name of the
current statistical matrix. It is used instead of E Q by the three
statistical plot types—Scatter, Bar, and Histogram.
22-12 Plotting