Creating A Directory - HP -28S Manual

Add R 1 and the reciprocal.
G
3
2
1 'Rl+INV(INV(R2)+INV(
R3»'
The resulting expression represents
Rtotal'
You could key in this expression directly, taking care to add parenthe-
ses where necessary. Every expression is equivalent to a stack
calculation, so you can choose the method that is easier for you.
Later in this chapter you'll store this expression in a variable, but first
create a directory to group together the examples in this chapter.
Creating a Directory
A directory is a set of variables. Right now you're working in the
HOME directory-a built-in directory that exists even after MEMORY
RESET. In this chapter you'll create a subdirectory within HOME, and
then subdirectories within that subdirectory.
Here are some concepts about directories that you'll use in this
chapter.
• Only one directory can be the
current directory;
only its variables
appear in the USER menu.
• If a directory A contains a directory
B,
then A is called the
parent
directory
of B, and B is called a
subdirectory
of A.
• If you start at the current directory and find its parent directory,
and then the next parent directory, and so on, you always return to
HOME. This sequence of directories (in the reverse order) is called
the
current path.
You can check the current path by executing the command PATH.
Select the MEMORY menu .
• , MEMORY
I
2:
60 4: Repeating Calculations
1: 'Rl+INV<INV(R2)+INV(
R3»'
GImlm:l!lmmimilCIllml~
I