Casio fx-9860GII - 2.4 Finding a numerical derivative

Using a graphic display calculator
© Oxford University Press 2012: this may be reproduced for class use solely for the purchaser’s institute
Casio fx-9860GII
Press
SHIF T
F5
G-Solv.
Press
F3
MIN to fi nd the minimum point.
The calculator displays the local minimum at the point (2.23, −7.24).
2.4 Finding a numerical derivative
Using the calculator it is possible to fi nd the numerical value of any derivative
for any value of x. The calculator will not, however, differentiate a function
algebraically. This is equivalent to fi nding the gradient at a point graphically
(see Section 2.1 example 29).
Example 32
If
y
x
x
=
+3
,
evaluate
d
d
y
x
x =2
Press
MENU
. You will see the dialog box as shown on the right.
Choose 1: RUN·MAT and press
EXE
.
Press
EXIT
until you see the menu on the right, then press
F4
MATH.
Press
F4
d
dx
to open the differentiation template.
The calculator shows that the value of the fi rst derivative of
y
x
x
=
+3
is
−0.75 when x = 2.
31