Operation Manual

Math, Angle, and Test Operations 2-7
8202MATH.DOC TI-82, Chapter 2, English Bob Fedorisko Revised: 02/09/01 12:20 PM Printed:
02/09/01 12:36 PM Page 7 of 16
nDeriv(
nDeriv(
(numerical derivative,
MATH MATH
item
8
) returns an approximate
derivative of
expression
with respect to
variable
, given the
value
at which
to calculate the derivative, and
H
(optional; if none is specified, 1
E
.
3 is
used).
nDeriv(
expression
,
variable
,
value
)
or
nDeriv(
expression
,
variable
,
value
,
H
)
nDeriv(
uses the symmetric difference quotient method, which
approximates the numerical derivative value as the slope of the secant line
through the points:
(
value
–
H
,
expression
(
value
–
H
)) and
(
value
+
H
,
expression
(
value
+
H
))
As
H
gets smaller, the approximation usually gets more accurate.
nDeriv(
can be used once in
expression
. Because of the method,
nDeriv(
can return a false derivative value at a nondifferentiable point.
fnInt(
fnInt(
(function integral,
MATH MATH
item
9
) returns the numerical integral
(Gauss-Kronrod method) of
expression
with respect to
variable
, given
lower
limit,
upper
limit, and a
tolerance
(optional; if none is specified, 1
E
.
5
is used).
fnInt(
expression
,
variable
,
lower
,
upper
)
or
fnInt(
expression
,
variable
,
lower
,
upper
,
tolerance
)
fnInt(
is not valid in
expression
.