HP 48gII - Manual (Page 177)

Page 5-6
Note: Recall that, to use these, or any other functions in the RPN mode,
you must enter the argument first, and then the function. For example, the
example for TEXPAND, in RPN mode will be set up as:
³„¸+~x+~y`
At this point, select function TEXPAND from menu ALG (or directly from
the catalog ‚N), to complete the operation.
Other forms of substitution in algebraic expressions
Functions SUBST, shown above, is used to substitute a variable in an
expression. A second form of substitution can be accomplished by using the
‚¦ (associated with the I key). For example, in ALG mode, the
following entry will substitute the value x = 2 in the expression x+x
2 . The
figure to the left shows the way to enter the expression (the substituted value,
x=2, must be enclosed in parentheses) before pressing `. After the `
key is pressed, the result is shown in the right-hand figure:
In RPN mode, this can be accomplished by entering first the expression where
the substitution will be performed (x+x
2 ), followed by a list (see Chapter 8)
containing the substitution variable, an space, and the value to be substituted,
i.e., {x 2}. The final step is to press the keystroke combination: ‚¦.
The required keystrokes are the following:
³~„x+~„xQ2`
„ä~„x#2` ‚¦`