Section 4
Using HP-41C Functions
As you may have noticed by now, not all of the functions available in the HP-41C are printed on the keyboard. In all, the HP-41C has over 130 standard functions, 68 of which are immediately accessible by pressing function keys on the keyboard.
The rest of the HP-41C functions are accessible in different ways: from the display or by assigning them to the USER mode keyboard. You simply press XEQ execute and enter the function name into the display in ALPHA mode. Or even easier, you can assign the function name to a key location using the ASN (assign) function and execute the function at the press of a single key in USER mode.
With a couple of exceptions, all functions in the HP-41C can be executed in this manner. Section 6 lists and explains most standard HP-41C functions except for programming functions. In addition, the function index in the back of this handbook (page 267) list all HP-41C standard functions.
Executing Functions From the Display
Here is how it is done. Let’s compute the factorial ( FACT ) of 6. FACT is one of the functions not available on the normal keyboard.
To begin, key in the number 6 and press XEQ, the HP-41C will place the word XEQ and _ (underscore) prompts in the display, like this:
Keystrokes Display    
6  6 _   The number.
XEQ   XEQ _ _   The HP-41C is asking: Execute what?
All you do now is place the name of the function you wish to execute into the display. Initially, the HP-41C prompts you with _ _ for a two-digit numeric label. As soon as you press ALPHA to enter your function name, the prompt changes to a single _, prompting you for ALPHA characters one at a time. When the HP-41C prompts you for an ALPHA character, simply press the keys associated with the desired characters. Later, in part II, you will see how to use XEQ to execute programs with numeric labels by specifying a label number instead of an ALPHA name.