Texas Instruments TITANIUM TI-89 - Manual (Page 290)

Constants and Measurement Units 290
• 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
2
units.
Note: NONE is not available for base categories such as Length and Mass that have no
components.
Creating Your Own User-Defined Units Creating Your Own User-Defined Units Creating Your Own User-Defined Units Creating Your Own User-Defined Units
In any category, you can expand the list of available units by defining a new unit in terms
of one or more pre-defined units. You can also use “standalone” units.
Why Use Your Own Units? Why Use Your Own Units? Why Use Your Own Units? Why Use Your Own Units?
Some example reasons to create a unit are:
• You want to enter length values in dekameters. Define 10_m as a new unit named
_dm.
• Instead of entering _m/_s
2
as an acceleration unit, you define that combination of
units as a single unit named _ms2.
• You want to calculate how many times someone blinks. You can use _blinks as a
valid unit without defining it. This “standalone” unit is treated similar to a variable that
is not defined. For instance, 3_blinks is treated the same as 3a.
Note: If you create a user-defined unit for an existing category, you can select it from the
UNITS dialog box menu. But you cannot use 3 to select the unit as a default for
displayed results.