Texas Instruments TITANIUM TI-89 User Manual
Page 274
Symbolic Manipulation
274
-
Clear the history area (
,
8
) or delete unneeded history pairs.
-
You can also use
,
9
to reduce the number of history pairs that will be saved.
•
Use
3 to set Exact/Approx = APPROXIMATE. (For results that have a large
number of digits, this uses less memory than
AUTO
or EXACT. For results that have
only a few digits, this uses more memory.)
Simplifying Problems
Simplifying Problems
Simplifying Problems
Simplifying Problems
•
Split the problem into parts.
-
Split
solve(
a†b=0,
var)
into
solve(
a=0,
var)
and
solve(
b=0,var
)
. Solve each part and
combine the results.
•
If several undefined variables occur only in a certain combination, replace that
combination with a single variable.
-
If m and c occur only as
m
†
c
2
, substitute e for
m
†
c
2
.
-
In the expression
, substitute c for
(a+b)
and use
. In
the solution, replace c with
(a+b)
.
•
For expressions combined over a common denominator, replace sums in
denominators with unique new undefined variables.
-
In the expression
, substitute d for
and
are
. In the solution, replace d with
.
•
Substitute known numeric values for undefined variables at an earlier stage,
particularly if they are simple integers or fractions.
a b
+
(
)
2
a b
+
(
)
2
+
1
a b
+
(
)
2
–
--------------------------------------------------
c
2
c
2
+
1 c
2
–
---------------------
x
a
2
b
2
+
c
+
------------------------------
y
a
2
b
2
+
c
+
------------------------------
+
a
2
b
2
+
c
+
x
d
---
y
d
---
+
a
2
b
2
+
c
+