HP 42S - Manual (Page 6)

IMPORTANT: For sake of simplicity sometimes we will use / instead of ÷.
2.5 Menus
Not all functions of HP-42S are visible above the keys. It has menus with much more functions. The
menus are
ALPHA, MODES, DISP, CLEAR, SOLVER, ∫f(x), MATRIX, STAT, BASE, CONVERT,
FLAGS, PROB, CUSTOM, PGM. FCN, PRINT, TOP.FCN and CATALOG.
2.6 DISP Menu
The DISP menu is the first menu we have to see. It is above E key. So start by pressing ▀ DISP.
When you do this the DISP menu appears in the first line with the following functions.
FIX, SCI, ENG, ALL, RDX., RDX,
These functions appears just above ∑+, 1/x,√x, LOG, LN and XEQ. Now with DISP menu active
those keys don't represent their original functions but those of DISP menu. The same happens with
all menus.
2.6.1 The FIX function.
The FIX “function” is not a function in the mathematical sense, but a calculator function. By using
FIX function the display becomes with a fixed number of digits after decimal point.
Ok, press FIX. (I mean ∑+ with DISP menu active)
When you do this what appears is
FIX _ _
Then you have to enter a number up to 11. Example
FIX 0 4 set calculator to have 4 digits of precision after the decimal point. A number like π will
appear as
3.1416
and √2 will appear as 1.4142.
(You can verify this by doing ▀ π and 2 √x respectively)
If you put FIX 0 9 than those numbers will appear as
3.141592654
and
1.414213562.
It is important to say that this is not the actual precision the calculator will have but just the display
precision. To see all calculator precision you have to press ALL in DISP menu (above LOG key).
By doing so those numbers will appear as
3.14159265359
and