Menus, Fix, Sci, Eng, All, Rdx., Rdx

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