Texas Instruments TI-89 Manual Book page 91

Finding the Zeros of
an Expression
Tip: For ‚ or , type ¥ à or
¥ Â .You can also use
2 I 8 or 2 ¿ 2 to
select them from a menu.
Finding Proper
Fractions and
Common
Denominators
Note: You can use
comDenom with an
expression, list, or matrix.
74 Chapter 3: Symbolic Manipulation
( „
Use the ) function.
zeros 4
zeros(expression, var)
Use the expression
x ù sin(x) + cos(x) .
Find the zeros with respect to
in the interval and
0  x
( „
Use the
propFrac
propFrac(rational expression [,var])
comDenom(expression [,var])
Find a proper fraction for the
expression
4
(x ì 2xñ + x) / (2xñ + x + 4)
Then transform the answer into
a ratio of a fully expanded
numerator and a fully expanded
denominator.
Notice that and
propFrac
perform opposite
comDenom
operations.
In this example:
31 x + 60
¦
is the remainder of
8
xñ
x
¦
ì ì
is the quotient.
15/8
2 4
x
Use the "with"
.
x  3
operator to specify
the interval.
( „
) and
7 comDenom
for proper fractions with respect
to a variable
for common denominators that collect for common denominators that collect
similar powers of this variable similar powers of this variable
.
If you do this example on your
TI-89 / TI-92 Plus, the propFrac
function scrolls off the top of the
screen.
4
ì 2xñ +x divided by
x
) functions.
6
.
2xñ +x+4