RPN Advanced 42 manual · Chapter 6 of 18

Modes and display

Angle units, rectangular or polar complex form, complex or real results, and how many digits the display shows.

6.1The MODES menu#

Open MODES with shift +/−. Page 1 picks the angle unit and the complex display form; page 2 picks whether results may be complex. A filled square marks the current choice. Defaults: DEG, rectangular, real results.

MODES page 1: DEG, RAD, GRD, then REC and POL. The display shows: x: 0.0000 / DEG■ RAD GRD REC■ POL. — MODES page 1: DEG, RAD, GRD, then REC and POL.

MODES page 2: CPX (complex results allowed) and RL (real results only). The display shows: x: 0.0000 / CPX REA■ . — MODES page 2: CPX (complex results allowed) and RL (real results only).

Item	Menu key	What it does
DEG	`Σ+`	Angles in degrees (360 per turn). The default.
RAD	`1/x`	Angles in radians ( $2\pi$ per turn).
GRD	`√x`	Angles in grads (400 per turn).
REC	`LN`	Complex numbers shown as x and y parts.
POL	`XEQ`	Complex numbers shown as radius and angle.
CPX (page 2)	`Σ+`	Square roots and logarithms of negative numbers give complex answers.
RL (page 2)	`1/x`	Those give an error instead. The default.

6.2Set the angle unit#

Example 6.1

Switch to grads and take an arctangent

Open MODES and press GRD.
⇧MODES+/−√x
Close the menu, type 1 and press shift TAN.
EXIT1⇧ATANTAN

6.3Rectangular or polar form, complex or real results#

Example 6.2

Real results only: square root of a negative number

4, +/−, square root gives an error in the default mode.
4+/−√x

Example 6.3

Allow complex results

Open MODES, go to page 2 and choose CPX, then close the menu.
⇧MODES+/−▼Σ+EXIT
Now the square root of −4 is 2i.
4+/−√x

6.4Choose the display format#

Open DISP with shift E. FIX shows a fixed number of decimals, SCI scientific notation with a fixed number of digits, ENG engineering notation (exponent a multiple of 3), and ALL shows every digit that matters. The default is FIX 4. The calculation always keeps 12 digits; only the display changes.

The DISP menu: FIX, SCI, ENG, ALL and the radix keys R. (point) and R, (comma). The marked one is active. The display shows: x: 0.0000 / FIX■ SCI ENG ALL R.■ R,. — The DISP menu: FIX, SCI, ENG, ALL and the radix keys R. (point) and R, (comma). The marked one is active.

After FIX, SCI or ENG, type the number of digits as two keys, for example 0 3, or one digit then ENTER.

Example 6.4

Show 3 decimal places

Open DISP, press FIX, and type 0 3.
⇧DISPEΣ+03
Close the menu and calculate the square root of 2.
EXIT2√x

Example 6.5

Scientific notation with 3 digits

Open DISP, press SCI, type 0 3.
⇧DISPE1/x03EXIT
Enter 12345 and press ENTER to finish it.
12345ENTER

Example 6.6

Engineering notation

Open DISP, press ENG, type 0 3, close.
⇧DISPE√x03EXIT
Multiply 12345 by 1.
12345ENTER1×

Example 6.7

Show every digit with ALL

Open DISP and press ALL (fourth key), close, then calculate 1/3.
⇧DISPELOGEXIT1ENTER3÷

HP-42S is a trademark of HP Inc.. Trident Calculator is an independent product by South View Studios and is not affiliated with, sponsored by or endorsed by HP. The name is used only to describe the kind of calculator this model resembles; Trident's names, keys, display, fonts and software are its own clean-room design.