Casio FX-7400G PLUS User Manual page 59

This average, which is called the central difference , is expressed as:
f (a + ∆x) – f (a)
1
f '(a) = –– ––––––––––––– + –––––––––– –––
2 ∆x
f (a + ∆x) – f (a – ∆x)
= –––––––––– –––––––
2 ∆x
u u u u u To perform a differential calculation
Example To determine the derivative at point
y x
= + 4
3
x
∆
= 1
f(x)
Input the function
AK2(CALC)[1(
TMd+eTx
+T-g,
x a
Input point = for which you want to determine the derivative.
d,
Input ∆ x
, which is the increase/decrease of
bE-f)
w
f(x)
• In the function
ables (A through Z) are treated as constants, and the value currently assigned to
that variable is applied during the calculation.
• Input of ∆ x and the closing parenthesis can be omitted. If you omit ∆
lator automatically uses a value for ∆
which you specified as the point for which you wanted to determine the deriva-
tive.
• Discontinuous points or sections with drastic fluctuation can adversely affect pre-
cision or even cause an error.
• Note that you cannot use differential calculation inside of a differential calculation
term.
Differential Calculations
f (a) – f (a – ∆x)
∆x
x x
+ – 6, when the increase/decrease of
2
– 5
E
.
d/dx
)
, only X can be used as a variable in expressions. Other vari-
x
x
= 3 for the function
x
.
that is appropriate for the value of
Chapter 3
x
is defined as
x
, the calcu-
x a
= ,
45