Casio fx-9750G PLUS - Manual (Page 84)

56
This average, which is called the central difference, is expressed as:
u u u u u To perform a differential calculation
Example To determine the derivative at point x = 3 for the function
y = x 3 + 4 x 2 + x – 6, when the increase/decrease of x is defined
as A A A A A
x = 1
E
– 5
Input the function f (x) .
A K4 (CALC)2( d/dx )vMd+evx+v-g,
Input point x = a for which you want to determine the derivative.
d,
Input A x , which is the increase/decrease of x .
bE-f)
w
• In the function f (x) , only X can be used as a variable in expressions. Other
variables (A through Z, r , θ) are treated as constants, and the value currently
assigned to that variable is applied during the calculation.
• Input of A x and the closing parenthesis can be omitted. If you omit A x , the
calculator automatically uses a value for A x that is appropriate for the deriva-
tive value you are trying to determine.
• Discontinuous points or sections with drastic fluctuation can adversely affect
precision or even cause an error.
3 - 2
Differential Calculations
1 f (a + Ax) – f (a) f (a) – f (a – Ax)
f '(a) = –– ––––––––––––– + –––––––––––––
2 A x A x
f (a + Ax) – f (a – Ax)
= –––––––––––––––––
2
A x