Texas Instruments TI-89 Manual Book page 79

APPROXIMATE
Setting
62 Chapter 3: Symbolic Manipulation
When
Exact/Approx = APPROXIMATE
rational numbers and irrational constants to floating-point. However,
there are exceptions:
¦
Certain built-in functions that expect one of their arguments to be
an integer will convert that number to an integer if possible. For
example: d
(y(x), x, 2.0)
¦
Whole-number floating-point exponents are converted to integers.
2.0
For example: x transforms to
setting.
Functions such as solve
and approximate numeric techniques. These functions skip all or
some of their exact symbolic techniques in the
setting.
Advantages
If exact results are not
needed, this might save
time and/or use less
memory than the
EXACT
setting.
Approximate results are
sometimes more
compact and
comprehensible than
exact results.
If you do not plan to use
symbolic computations,
approximate results are
similar to familiar,
traditional numeric
calculators.
, the
TI-89 / TI-92 Plus
transforms to d
(y(x), x, 2)
2
x even in the
and (integrate) can use both exact symbolic
Disadvantages
Results with undefined variables or
functions often exhibit incomplete
cancellation. For example, a coefficient
that should be might be displayed as a
0
small magnitude such as
Symbolic operations such as limits and
integration are less likely to give
satisfying results in the
setting.
Approximate results are sometimes less
compact and comprehensible than exact
results. For example, you may prefer to
see instead of
1/7 .142857
converts
.
APPROXIMATE
APPROXIMATE
.
1.23457 -11
E
APPROXIMATE
.