Texas Instruments TITANIUM TI-89 - Manual (Page 867)

Appendix A: Functions and Instructions 867
rowSwap() MATH/Matrix/Row ops menu
rowSwap( matrix1 , rIndex1 , rIndex2 )
⇒ ⇒ ⇒ ⇒ matrix
Returns matrix1 with rows rIndex1 and rIndex2
exchanged.
[1,2;3,4;5,6]! Mat ¸





 1 2
3 4
5 6
rowSwap(Mat,1,3) ¸





 5 6
3 4
1 2
RplcPic CATALOG
RplcPic picVar [, row ][, column ]
Clears the Graph screen and places picture picVar
at pixel coordinates ( row , column ). If you do not
want to clear the screen, use RclPic .
picVar must be a picture data type variable. row
and column , if included, specify the pixel
coordinates of the upper left corner of the picture.
Default coordinates are (0, 0).
Note: For less than full-screen pictures, only the
area affected by the new picture is cleared.
rref() MATH/Matrix menu
rref( matrix1 [, tol ]) ⇒ ⇒ ⇒ ⇒ matrix
Returns the reduced row echelon form of matrix1 .
rref([л2,л2,0,л6;1,л1,9,л9;
л
5,2,4,л4]) ¸







 1 0 0 66/71
0 1 0
147
71
0 0 1 л 62/71
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:
5 E л 14 щ max(dim( matrix1 ))
ù rowNorm( matrix1 )
Note: See also ref() .
rref([a,b,x;c,d,y]) ¸








1 0
dø x-bø y
aø d-bø c
0 1
ë (cø x-aø y)
aø d-bø c
sec() MATH/Trig menu
sec( expression1 )
⇒ ⇒ ⇒ ⇒ expression
sec( list1 ) ⇒ ⇒ ⇒ ⇒ list
Returns the secant of expression1 or returns a list
containing the secants of all elements in list1 .
Note: The result is returned as a degree, gradian
or radian angle, according to the current angle
mode setting.
In Degree angle mode:
sec(45) ¸ (2)
sec({1,2.3,4}) ¸
{
1
cos(1)
1.000…
1
cos(4)}