HP -18C Owner's Manual page 144

In translating this formula into one that the solver can understand,
there are several rules to keep in mind:
• There is no limit on the length of the formula as long as there is
sufficient memory to store it.
• User-variable names can be a maximum of 10 characters long (no
spaces allowed) and must be all one word. You cannot use the
characters
+, -,
x,
7, "', (, ),
<, > ,
=,
and :. For example, you
could rewrite the T-bill formula as:
YIELD
=
$10,000 - PRICE x 360 days
' - P/ CE MA j URITY
Shortened names, all uppercase letters
• The first four or five characters of the user-variable names become
menu labels in the custom menu. Therefore, make sure no two vari-
ables have the same first four or five characters.
• Constants must be keyed in as numbers without digit separators or
other characters. For example:
Numbers written properly
/ '
"-
YIELD
10000 - PRICE 360
x
PRICE MATURITY
• Write the formula on one line. When necessary, use parentheses to
control the order of calculations. Without parentheses, the solver
does calculations using these algebraic rules:
Exponentiation before multiplication and division.
For example, a
formula typed in as
AXS"'3=C
is interpreted as A x B3
=
C. B is
raised to the 3rd power and then multiplied by A. To raise A x B to
the 3rd power, write the formula:
(AxS) A3=C.
142 9: The Formula Solver