Texas Instruments TI-89 - Page 453

436 Appendix A: Functions and Instructions
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 436 of 132
deSolve(2ndOrderOde and boundaryCondition1 and
boundaryCondition2, independentVar,
dependentVar)
⇒
a particular solution
Returns a particular solution that satisfies
2ndOrderOde
and has specified values at two
different points.
deSolve(w''
ì
2w'/x+(9+2/x^2)w=
x
ù
e
^(x) and w(p/6)=0 and
w(p/3)=0,x,w)
¸
w=
e
p
3
ø
x
ø
cos(3
ø
x)
10
ì
e
p
6
ø
x
ø
sin(3
ø
x)
10
+
x
⋅
e
x
10
det()
MATH/Matrix menu
det(squareMatrix
[
, tol
]
)
⇒
expression
Returns the determinant of
squareMatrix
.
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
ë
14
ù
max(dim(squareMatrix))
ù
rowNorm(squareMatrix)
det([a,b;c,d])
¸
a
ø
d
ì
b
ø
c
det([1,2;3,4])
¸ ë
2
det(identity(3)
ì
x
ù
[1,
ë
2,3;
ë
2,4,
1
;
ë
6,
ë
2,7
])
¸
ë
(
98
ø
x
ò
ì
55
ø
x
ñ
+
1
2
ø
x
ì
1)
[1
E
20,1;0,1]
!
mat1
[
1.
E
20 1
0 1
]
d
et
(
mat
1)
¸
0
d
et
(
mat
1
,.
1)
¸
1
.
E
20
diag()
MATH/Matrix menu
diag(list)
⇒
matrix
diag(rowMatrix)
⇒
matrix
diag(columnMatrix)
⇒
matrix
Returns a matrix with the values in the
argument list or matrix in its main diagonal.
diag({2,4,6})
¸




2 0 0
0 4 0
0 0 6
diag(squareMatrix)
⇒
rowMatrix
Returns a row matrix containing the
elements from the main diagonal of
squareMatrix
.
squareMatrix
must be square.
[4,6,8;1,2,3;5,7,9]
¸




4 6 8
1 2 3
5 7 9
diag(ans(1))
¸
[4 2 9]