Zoombox Catalog - Texas Instruments TITANIUM TI-89 User Manual

You can also (or instead) include unknowns that
do not appear in the expressions. For example,
you can include z as an unknown to extend the
previous example to two parallel intersecting
cylinders of radius r. The cylinder zeros illustrate
how families of zeros might contain arbitrary
constants in the form
suffix from 1 through 255. The suffix resets to 1
when you use
For polynomial systems, computation time or
memory exhaustion may depend strongly on the
order in which you list unknowns. If your initial
choice exhausts memory or your patience, try
rearranging the variables in the expressions
and/or
If you do not include any guesses and if any
expression is non-polynomial in any variable but
all expressions are linear in the unknowns,
zeros()
determine all real zeros.
If a system is neither polynomial in all of its
variables nor linear in its unknowns,
determines at most one zero using an
approximate iterative method. To do so, the
number of unknowns must equal the number of
expressions, and all other variables in the
expressions must simplify to numbers.
Each unknown starts at its guessed value if there
is one; otherwise, it starts at 0.0.
Use guesses to seek additional zeros one by one.
For convergence, a guess may have to be rather
close to a zero.
ZoomBox
CATALOG
ZoomBox
Displays the Graph screen, lets you draw a box
that defines a new viewing window, and updates
the window.
896
ck
, where
or ƒ
ClrHome 8:Clear Home
list.
varOrGuess
uses Gaussian elimination to attempt to
ans(1)[2] ¸
zeros({x^2+y^2 ì r^2,
(x ì r)^2+y^2 ì r^2},{x,y,z}) ¸
k
is an integer
.
zeros({x+
}) ¸
zeros({
{y,z}) ¸
zeros()
zeros({
{y,z=2 p }) ¸
In function graphing mode:
1.25x ù cos(x) ! y1(x) ¸
ZoomStd:ZoomBox ¸
The display after defining
¸ the second time.
Appendix A: Functions and Instructions


r


2

r
ë

2
^(z) ù y ì 1,x ì y ì sin(z)},{x,y
e
e
ø sin(z)+1 ë (sin(z) ì 1)

z

e
+1
z
^(z) ù y ì 1, ë y ì sin(z)},
e
[
.041...
^(z) ù y ì 1, ë y ì sin(z)},
e
[
.001...
ZoomBox
r ø r

ë 3

2 2
ø r

3
@1

2

ø r
3
@1

2


e
+1
z
]
3.183...
]
6.281...
Done
1st corner
2nd corner
by pressing