Calculator User Manual

Chapter 3: Math, Calculus, and Test Operations
55
03MATH.DOC TI-86, Chap 3, US English Bob Fedorisko Revised: 02/13/01 2:19 PM Printed: 02/13/01 3:00 PM Page 55 of 1003MATH.DOC TI-86, Chap 3, US English Bob Fedorisko Revised: 02/13/01 2:19 PM Printed: 02/13/01 3:00 PM Page 55 of 10
The built-in variable
d
defines the step size in calculating
nDer(
(in
dxNDer
differentiation
mode only) and
arc(
. The built-in variable
tol
defines the tolerance in calculating
fnInt(
,
fMin(
,
fMax(
, and
arc(
. The value of each must be >0. These factors affect the accuracy of the
calculations. As
d
becomes smaller, the approximation typically is more accurate. For
example,
nDer(A^3,A,5)
returns
75.0001
if
d
=.01
, but returns
75
if
d
=.0001
(Appendix).
The function integral error value is stored to the variable
fnIntErr
(Appendix).
For
arc(
and
fnInt(
while
dxDer1
mode is set, these functions are not valid in
expression
:
evalF(
,
der1(
,
der2(
,
fMin(
,
fMax(
,
nDer(
,
seq(
, and any equation variable, such as
y1
.
You can approximate the fourth derivative at the current value of x with this formula:
nDer(nDer(der2(x^4,x),x),x)
.
The TEST (Relational) Menu
- ˜
= = < >
‚4ƒ
valueA
==
valueB
(equal to) Returns
1
if
valueA
is equal to
valueB
; returns
0
if not equal;
valueA
and
valueB
can be real or complex numbers, lists, vectors, matrices, or strings
valueA
<
valueB
(less than) Returns
1
if
valueA
is less than
valueB
; returns
0
if
valueA
is not less than
valueB
;
valueA
and
valueB
must be real numbers or lists
valueA
>
valueB
(greater than) Returns
1
if
valueA
is greater than
valueB
; returns
0
if
valueA
is not
greater than
valueB
;
valueA
and
valueB
must be real numbers or lists
valueA

valueB
(less than or equal to) Returns
1
if
valueA
is less than or equal to
valueB
; returns
0
if
valueA
is not less than or equal to
valueB
;
valueA
and
valueB
must be real numbers or lists
Relational functions are valid
for two lists of the same
length. When
valueA
and
valueB
are lists, a list of
results calculated element by
element is returned.