HP HP-28S - Page 63

This is one of the benefits of directories: If you put general-purpose
programs such as RENAME in the HOME directory, you can always exe-
cute them but they don't clutter up the USER menu.
Now you can work in the new directory EE.
Drop the two path lists from the stack.
[ DROP I [ DROP I '""2:-:-------------,
1: 'Rl + INV(lNV(R2)+ INV(
R3»'
------
Store the expression in a variable named EQl (equation 1). You'll see
the reason for this name later.
c:J EQ1 [STO I
IL _____ I
The variable EQl appears in the USER menu.
Let's assume that you'll use this expression for a variety of problems,
each of which you want to treat independently. To do so, you can put
the values for each problem in a subdirectory for that problem.
Create a subdirectory SPl (series-parallel 1) for the first problem.
CRDIR [ENTER I 2:
c:J SP1 [ ENTER I 1
3
•
I
~mm ___ _
The name of the new subdirectory appears in the USER menu. Press
the menu key to switch to SPl.
SPl
I!L.-- ___ I
The USER menu is empty again because the current directory (SP1) is
empty.
62 4: Repeating Calculations