28
Example in MathPrint™ mode
Example in Classic mode
Classic:
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 these points.
As
H
becomes smaller, the approximation usually becomes
more accurate. In MathPrint™ mode, the default
H
is 1
E
M
3.
You can switch to Classic mode to change
H
for
investigations.
You can use
nDeriv(
once in
expression
. Because of the
method used to calculate
nDeriv(
, the calculator can return a
false derivative value at a nondifferentiable point.
³
Problem
Find the slope of the tangent line to the curve f(x) = x
3
– 4x at
x =
What do you notice? (Fix 3 decimal places.)
% A % A
z F T
5
z ""
M
1
<
% A % A
z F T
5
z
%`z
%`M
1
)
<
f
′
x
( )
f x
ε
+
(
)
f x
ε
–
(
)
–
2
ε
-----------------------------------------
=
2
3
-------
