Classic CAS manual · Chapter 5 of 16

Modes and settings

Calculation mode, angle unit, display digits and real or complex results.

5.1Open the settings#

Open Settings with menu then 9, or from the Home menu with home then 3. The form lists four settings; use ▲ and ▼ to pick one, ◀ and ▶ to change it, and enter to move on. When you press enter on the last setting, the form closes and the choices take effect.

The Settings form with the defaults: Auto, Radian, Float 6, Real. The display shows: Settings / Calculation Mode: [Auto] Exact Approximate / Angle: [Radian] Degree Gradian / Display Digits: Float Float 1 Float 2 Float 3 Float 4 Float 5 [Float 6] Float 7 Float 8 Float 9 Float 10 Float 11 Float 12 Fix 0 Fix 1 Fix 2 Fix 3 Fix 4 Fix 5 Fix 6 Fix 7 Fix 8 Fix 9 Fix 10 Fix 11 Fix 12 / Real or Complex: [Real] Rectangular. — The Settings form with the defaults: Auto, Radian, Float 6, Real.

Setting	Choices	Default
Calculation Mode	Auto, Exact, Approximate	Auto
Angle	Radian, Degree, Gradian	Radian
Display Digits	Float, Float 1 to Float 12, Fix 0 to Fix 12	Float 6
Real or Complex	Real, Rectangular	Real

menu 9
▼ / ▲ pick a setting
◀ / ▶ change it
enter on each line to finish

Changing a setting.

5.2Calculation mode: Auto, Exact, Approximate#

Auto keeps exact answers unless a decimal appears in your input. Exact always shows exact forms, even for decimal input. Approximate turns every answer into a decimal. The indicator at the top of the screen shows the current mode.

Example 5.1

Approximate mode

Open Settings, press right twice to choose Approximate, and press enter four times.
menu9▶▶enterenterenterenter
Type 1/3 and press enter.
1÷3enter

Example 5.2

Exact mode

Open Settings, press right once to choose Exact, and press enter four times.
menu9▶enterenterenterenter
Type 0.5 + 1/4.
0.5+1÷4enter

Example 5.3

Solve in Approximate mode

Switch to Approximate.
menu9▶▶enterenterenterenter
Solve x² = 2.
solve(x^2▶=2,x)enter

5.3Angle unit#

Radian is the default. Degree and Gradian change how sin, cos and tan read their angle, and how the inverse functions answer. Use ctrl°. to type a degree sign when you only need degrees once.

180^\circ=\pi\ \text{rad}=200\ \text{grad}

Angle units.

Example 5.4

Degree mode

Open Settings, press down, right, then enter three times.
menu9▼▶enterenterenter
Type sin(30).
sin(30)enter

Example 5.5

Gradian mode

Open Settings, press down, right, right, then enter three times.
menu9▼▶▶enterenterenter
Type sin(100) and press ctrl enter.
sin(100)ctrl≈enter

5.4Display digits#

Float shows as many digits as needed up to the chosen count (Float alone means up to 12). Fix n always shows exactly n decimals. This only changes how decimal answers are shown, not how they are calculated.

Example 5.6

Fix 2

Open Settings, press down twice, then right nine times to reach Fix 2, then enter twice.
menu9▼▼▶▶▶▶▶▶▶▶▶enterenter
Type π and press ctrl enter.
πctrl≈enter

Example 5.7

Float 10

Open Settings, press down twice, right four times, then enter twice.
menu9▼▼▶▶▶▶enterenter
Type π and press ctrl enter.
πctrl≈enter

5.5Real or complex results#

In Real mode, the square root of a negative number is an error. In Rectangular mode, answers can have the form $a+bi$ . The tag a+bi appears at the top of the screen.

Real mode: the square root of −4 is a non-real result. The display shows: Error: Non-real result / Press any key to continue. — Real mode: the square root of −4 is a non-real result.

Example 5.8

Rectangular mode

Open Settings, press down three times, right once, then enter.
menu9▼▼▼▶enter
Type √(−4).
ctrl√x²((−)4)▶enter

TI-Nspire CX CAS is a trademark of Texas Instruments Incorporated. Trident Calculator is an independent product by South View Studios and is not affiliated with, sponsored by or endorsed by Texas Instruments. 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.