Texas Instruments TI-89 Titanium User Manual page 231

APPROXIMATE Setting
When Exact/Approx = APPROXIMATE, the handheld converts 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:
to
d(y(x), x, 2).
• Whole-number floating-point exponents are converted to integers. For example: x
transforms to x
Functions such as
numeric techniques. These functions skip all or some of their exact symbolic techniques
in the APPROXIMATE 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.
Symbolic Manipulation
2
even in the APPROXIMATE setting.
and ‰ (integrate) can use both exact symbolic and approximate
solve
Disadvantages
Results with undefined variables or
functions often exhibit incomplete
cancellation. For example, a
coefficient that should be 0 might be
displayed as a small magnitude such
as 1.23457E - 11.
transforms
d(y(x), x, 2.0)
2.0
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