Casio fx-9860G SD - Manual (Page 96)

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k Differential Calculations
[OPTN]-[CALC]-[d /dx]
To perform differential calculations, first display the function analysis menu, and then input
the values using the syntax below.
K 4(CALC)2( d / dx ) f(x) , a ,tol)
The differentiation for this type of calculation is defined as:
In this definition, infinitesimal is replaced by a sufficiently small A x , with the value in the
neighborhood of f ' (a) calculated as:
In order to provide the best precision possible, this unit employs central difference to perform
differential calculations.
Using Differential Calculation in a Graph Function
• Omitting the tolerance (tol) value when using the differential command inside of a graph
function simplifies the calculation for drawing the graph. In such a case, precision is
sacrificed for the sake of faster drawing. The tolerance value is specified, the graph is
drawn with the same precision obtained when you normally perform a differential
calculation.
• You can also omit input of the derivative point by using the following format for the
differential graph: Y2=d/dx(Y1). In this case, the value of the X variable is used as the
derivative point.
2-5-2
Numerical Calculations
d
d/dx ( f (x), a)
⇒ ––– f (a)
dx
f (a + Ax) – f (a)
f '(a) = lim –––––––––––––
Ax
Ax →0
f (a + Ax) – f (a)
f '(a) –––––––––––––
Ax
( a : point for which you want to determine the
derivative, tol: tolerance)