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Chapter 20: A to Z Function and Instruction Reference     
323
20ATOZ.DOC   TI-86, Chap 20, US English   Bob Fedorisko   Revised: 02/13/01 2:42 PM   Printed: 02/13/01 3:05 PM   Page 323 of 118
20ATOZ.DOC   TI-86, Chap 20, US English   Bob Fedorisko   Revised: 02/13/01 2:42 PM   Printed: 02/13/01 3:05 PM   Page 323 of 118
nDer(
CALC menu
To view or set the value for
d
, press 
-
 
 
)
 to
display the tolerance
screen.
nDer(
expression
,
variable
,
value
)
Returns an approximate numerical derivative of
expression 
with respect to variable evaluated at a real
or complex value. The approximate numerical
derivative is the slope of the secant line through the
points:
(value
Nd,f(valueNd)) and (value+d,f(value+d))
As the step value 
d gets smaller, the approximation
usually gets more accurate.
For 
d=.001:
nDer(x^3,x,5) b
75.000001
For 
d=1
E
L4:
nDer(x^3,x,5) b
75
nDer(
expression
,
variable
)
Uses the current value of variable.
5¶x b
5
nDer(x^3,x) b
75
Negation:
 
L
 
a
L
 
number
   or   
L
 
(
expression
)
L
 
list
L
 
matrix
L
 
vector
Returns the negative of the real or complex argument.
L
2+5 b
3
L
(2+5) b
L
7
L
{0,
L
5,5} b
{0 5 
L
5}
norm
MATRX MATH menu
VECTR MATH menu
norm 
matrix
Returns the Frobenius norm of a real or complex
matrix
, calculated as:
G(real
2
+imaginary
2
)
where the sum is over all elements.
[[1,
L
2][
L
3,4]]¶MAT b
[[1 
L
2] 
[
L
3 4 ]]
norm MAT b
5.47722557505