Appendix A: Functions and Instructions 485
8992APPA.DOC TI-89 / TI-92 Plus: Appendix A (US English) Susan Gullord Revised: 02/23/01 1:48 PM Printed: 02/23/01 2:21 PM Page 485 of 132
PxlText CATALOG
PxlText string, row, col
Displays the Graph screen and places
character string string on the screen, starting
at pixel coordinates (row, col).
string is positioned with the upper-left corner
of its first character at the coordinates.
Note: Regraphing erases all drawn items.
TI-89: PxlText "sample
text",20,10 ¸
TI-92 Plus: PxlText "sample
text",20,50 ¸
PxlVert CATALOG
PxlVert col [, drawMode]
Draws a vertical line down the screen at pixel
position col.
If drawMode = 1, draws the line (default).
If drawMode = 0, turns off the line.
If drawMode = -1, turns a line that is on to off
or off to on (inverts pixels along the line).
Note: Regraphing erases all drawn items. See
also LineVert.
PxlVert 50,1 ¸
QR MATH/Matrix menu
QR matrix, qMatName, rMatName[ , tol]
Calculates the Householder QR factorization
of a real or complex matrix. The resulting Q
and R matrices are stored to the specified
MatNames. The Q matrix is unitary. The R
matrix is upper triangular.
Optionally, any matrix element is treated as
zero if its absolute value is less than tol. This
tolerance is used only if the matrix has
floating-point entries and does not contain
any symbolic variables that have not been
assigned a value. Otherwise, tol is ignored.
• If you use ¥¸ or set the mode to
Exact/Approx=APPROXIMATE, computations
are done using floating-point arithmetic.
• If tol is omitted or not used, the default
tolerance is calculated as:
5Eë14 ùmax(dim(matrix))
ùrowNorm(matrix)
The floating-point number (9.) in m1
causes results to be calculated in floating-
point form.
[1,2,3;4,5,6;7,8,9.]!m1 ¸
1
2 3
4 5 6
7 8 9.
QR m1,qm,rm ¸Done
qm ¸
.123… .904… .408…
.492… .301… ë.816…
.861… ë.301… .408…
rm ¸
8.124… 9.601… 11.078…
0. .904… 1.809…
0. 0. 0.
[m,n;o,p]!m1 ¸[]
m n
o p