User Manual

2-27
• You cannot use a differential, quadratic differential, integration, Σ , maximum/minimum value,
Solve, RndFix or log
a
b calculation expression inside a differential calculation term.
• In the Math input/output mode, the tolerance value is fixed at 1
E –10 and cannot be changed.
k Quadratic Differential Calculations [OPTN] - [CALC] - [ d
2
/ dx
2
]
After displaying the function analysis menu, you can input quadratic differentials using the
following syntax.
K4(CALC) * 3( d
2
/ dx
2
) f ( x ) ,a ,tol ) * fx-7400GIII: 3(CALC)
(
a : differential coefficient point, tol : tolerance)
Quadratic differential calculations produce an approximate differential value using the following
second order differential formula, which is based on Newton’s polynomial interpretation.
In this expression, values for “sufficiently small increments of
h ” are used to obtain a value that
approximates f " ( a ).
Example To determine the quadratic differential coefficient at the point where
x = 3 for the function y = x
3
+ 4 x
2
+ x – 6
Here we will use a tolerance tol = 1 E – 5
Input the function f ( x ).
AK4(CALC) * 3(
d
2
/ dx
2
) vMd+evx+v-g,
* fx-7400G
III: 3(CALC)
Input 3 as point a , which is the differential coefficient point.
d,
Input the tolerance value.
b5-f)
w
Quadratic Differential Calculation Precautions
• In the function f ( x ), only X can be used as a variable in expressions. Other variables (A
through Z excluding X, r ,  ) are treated as constants, and the value currently assigned to
that variable is applied during the calculation.
• Input of the tolerance (
tol ) value and the closing parenthesis can be omitted.
• Specify a tolerance (
tol ) value of 1 E –14 or greater. An error (Time Out) occurs whenever no
solution that satisfies the tolerance value can be obtained.
• The rules that apply for linear differential also apply when using a quadratic differential
calculation for the graph formula (see page 2-25).
d
2
d
2
––– (
f
(
x
),
a
)
⇒
–––
f
(
a
)
dx
2
dx
2
f
''(a) =
180h
2
2 f(a + 3h) – 27 f(a + 2h) + 270 f(a + h) – 490 f(a) + 270 f(a – h) – 27 f(a –2h) + 2 f(a – 3h)