# Functions Deriv And Dervx - HP 50g User Manual

Graphing calculator.

To calculate one-sided limits, add +0 or -0 to the value to the variable. A "+0"
means limit from the right, while a "-0" means limit from the left. For example,
the limit of
x
following keystrokes (ALG mode):
‚N~„l˜\$OK\$ R!ÜX-
1™@íX@Å1+0`
The result is as follows:
Derivatives
The derivative of a function f(x) at x = a is defined as the limit
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
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
as x approaches 1 from the left can be determined with the
1
df
( '
)
f
x
dx
(
)
f
x
h
lim
h
0
h
(
)
f
x
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