Texas Instruments PLUS TI-89 - Manual (Page 104)

Chapter 4: Constants and Measurement Units 87
04UNITS DOC TI-89/92Plus: Constants and Measurement Units (English) Susan Gullord Revised: 02/23/01 10:54 AM Printed: 02/23/01 2:12 PM Page 87 of 12
The SI and ENG/US systems of
measurement (set from Page 3
of the
MODE screen) use built-
in default units, which you
cannot change.
To find the default units for
these systems, refer to page 89.
To set custom defaults:
1. Press 3 … B 3 to set
Unit System = CUSTOM .
2. Press D to highlight SET
DEFAULTS .
3. Press B to display the
CUSTOM UNIT DEFAULTS
dialog box.
4. For each category, you can
highlight its default, press
B, and select a unit from the
list.
5. Press ¸ twice to save
your changes and exit the
MODE screen.
Many categories let you select NONE as the default unit.
This means that results in that
category are displayed in the
default units of its components.
For example, Area = Length ñ , so
Length is the component of
Area .
¦ If the defaults are Area = _acre and Length = _m (meters), area
results are shown with _acre units.
¦ If you set Area = NONE , area results are shown with _m ñ units.
Setting the Default Units for Displayed Results
All results involving units are displayed in the default unit for
that category. For example, if the default unit for Length is _m,
any length result is displayed in meters (even if you entered
_km or _ft in the calculation).
If You’re Using the
SI or ENG/US
System
Setting Custom
Defaults
Note: You can also use
setUnits()
or getUnits() to
set or return information
about default units. Refer to
Appendix A.
Tip: When the CUSTOM
UNIT DEFAULTS dialog box
first appears, it shows the
current default units.
What is the NONE
Default?
Note: NONE is not available
for base categories such as
Length and Mass that have
no components.
If Unit System=SI or ENG/US, the
Custom Units item is dimmed.
You cannot set a default for
individual categories.
You can also move the cursor by
typing the first letter of a unit.