HP 40gs User Manual
Page 265
Equation Writer
15-13
select the entire expression and press
, you
obtain:
However, if you type:
select the entire expression and press
, you
obtain 1.
How to enter infix
functions
An infix function is one that is typed between its
arguments. For example,
AND, |and MOD are infix
functions.You can either:
•
type them in Alpha mode and then enter their
arguments, or
•
select them from a CAS menu or by pressing an
appropriate key, provided that you have already
written and selected the first argument.
You move from one argument to the other by pressing
and
. The comma enables you to write a
complex number: when you type (1,2), the
parentheses are automatically placed when you type
the comma. If you want to type (–1,2), you must
select –1 before you type the comma.
How to enter prefix
functions
A prefix function is one that is typed before its arguments.
To enter a prefix function, you can:
•
type the first argument, select it, then select the
function from a menu, or
•
you can select the function from a menu, or by
directly entering it in Alpha mode, and then type the
arguments.
The following example illustrates the various ways of
entering a prefix function. Suppose you want to factor the
expression x
2
– 4, then find its value for x = 4. FACTOR is
the function for factoring, and it is found on the
menu.
SUBST is the function for substituting a value for a
variable in an expression, and it is also found in the
menu.
l
4
5
---
1
K
K 1
+
(
)
⋅
--------------------------
K
1
=
∞
∑
hp40g+.book Page 13 Friday, December 9, 2005 1:03 AM