HP 48GII, Руководство пользователя, Страница: 159 / 864

Page 3-34
Defining and using functions
Users can define their own functions by using the DEF command available
thought the keystroke sequence
„à
(associated with the
2
key). The
function must be entered in the following format:
Function_name(arguments) = expression_containing_arguments
For example, we could define a simple function
H(x) = ln(x+1) + exp(-x) .
Suppose that you have a need to evaluate this function for a number of
discrete values and, therefore, you want to be able to press a single button
and get the result you want without having to type the expression in the right-
hand side for each separate value. In the following example, we assume you
have set your calculator to ALG mode. Enter the following sequence of
keystrokes:
„à³~h„Ü~„x™‚Å
‚¹~„x+1™+„¸~„x`
The screen will look like this:
Press the
J
key, and you will notice that there is a new variable in your soft
menu key (
@@@H@@
). To see the contents of this variable press
‚
@@@H@@
. The screen
will show now:
Thus, the variable H contains a program defined by:
<< x ‘LN(x+1) + EXP(x)’ >>
This is a simple program in the default programming language of the HP 48
G series, and also incorporated in the HP 49 G series. This programming
language is called UserRPL. The program shown above is relatively simple
and consists of two parts, contained between the program containers
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