Texas Instruments TI-89 Voyage 200, User Manual

Page: 240 / 1008

Symbolic Manipulation 240
Using Exact, Approximate, and Auto Modes
Using Exact, Approximate, and Auto Modes Using Exact, Approximate, and Auto Modes
Using Exact, Approximate, and Auto Modes
The Exact/Approx mode settings, which are described briefly in Operating the Handheld ,
directly affect the precision and accuracy with which the TI-89 Titanium calculates a
result. This section describes these mode settings as they relate to symbolic
manipulation.
EXACT Setting EXACT Setting EXACT Setting EXACT Setting
When Exact/Approx = EXACT, the handheld uses exact rational arithmetic with up to
614 digits in the numerator and 614 digits in the denominator. The EXACT setting:
• Transforms irrational numbers to standard forms as much as possible without
approximating them. For example,
transforms to and
ln(1000)
transforms
to
3 ln(10)
.
• Converts floating-point numbers to rational numbers. For example, 0.25 transforms
to 1/4
.
The functions
solve
,
cSolve
,
zeros
,
cZeros
,
factor
,
‰
,
fMin
, and
fMax
use only exact
symbolic algorithms. These functions do not compute approximate solutions in the
EXACT setting.
• Some equations, such as
2
L
x
= x
, have solutions that cannot all be finitely
represented in terms of the functions and operators on the handheld.
12 2 3