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Page 13-3
Derivatives
The derivative of a function f(x) at x = a is defined as the limit
h
x f h x f
x f
dx
df
h
) ( ) (
lim ) ('
0
− +
= =
> −
Some examples of derivatives using this limit are shown in the following
screen shots:
Functions DERIV and DERVX
The function DERIV is used to take derivatives in terms of any independent
variable, while the function DERVX takes derivatives with respect to the CAS
default variable VX (typically ‘X’). While function DERVX is available directly
in the CALC menu, both functions are available in the DERIV.&INTEG sub-
menu within the CALCL menu (
„Ö
).
Function DERIV requires a function, say f(t), and an independent variable, say,
t, while function DERVX requires only a function of VX. Examples are shown
next in ALG mode. Recall that in RPN mode the arguments must be entered
before the function is applied.
The DERIV&INTEG menu
The functions available in this sub-menu are listed below: