Texas Instruments TI-89 Manual De Usuario
Symbolic Manipulation
241
•
With this kind of equation, EXACT will not compute approximate solutions. For
example,
example,
2
Lx
= x
has an approximate solution
x
≈
0.641186
, but it is not displayed in
the EXACT setting.
APPROXIMATE Setting
APPROXIMATE Setting
APPROXIMATE Setting
APPROXIMATE Setting
When Exact/Approx = APPROXIMATE, the handheld converts rational numbers and
irrational constants to floating-point. However, there are exceptions:
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:
convert that number to an integer if possible. For example:
d(y(x), x, 2.0)
transforms
to
d(y(x), x, 2).
•
Whole-number floating-point exponents are converted to integers. For example: x
2.0
transforms to x
2
even in the APPROXIMATE setting.
Advantages
Disadvantages
Results are exact.
As you use more complicated rational
numbers and irrational constants, calculations
can:
numbers and irrational constants, calculations
can:
•
Use more memory, which may exhaust the
memory before a solution is completed.
memory before a solution is completed.
•
Take more computing time.
•
Produce bulky results that are harder to
comprehend than a floating-point number.
comprehend than a floating-point number.