Casio fx-991ES PLUS User Manual
Page 15
E-14
°,
r
,
g
: These functions specify the angle unit. ° specifies degrees,
r
radians,
and
g
grads. Input a function from the menu that appears when you perform
the following key operation:
(DRG). See
3
.
,
: Exponential functions. Note that the input method is different
depending upon whether you are using Natural Display or Linear Display.
See
4
.
log
: Logarithmic function. Use the
5 key to input log
a
b as log (
a
,
b
). Base
10 is the default setting if you do not input anything for
a
. The
key also
can be used for input, but only while Natural Display is selected. In this
case, you must input a value for the base. See
5
.
ln
: Natural logarithm to base
e
. See
6
.
x
2
,
x
3
,
x
9, , , ,
x
−1
: Powers, power roots, and reciprocals. Note
that the input methods for
x
9, , , and are different depending upon
whether you are using Natural Display or Linear Display. See
7
.
Note: The following functions cannot be input in consecutive sequence:
x
2
,
x
3
,
x
9,
x
−1
. If you input 2
77, for example, the final 7 will be ignored. To
input 2
2
2
, input 2
7, press the B key, and then press 7.
: Function for performing numerical integration using the Gauss-Kronrod
method. Natural Display input syntax is
a
b
f
(
x
), while Linear Display input
syntax is
(
f
(
x
),
a
,
b
,
tol
).
tol
specifies tolerance, which becomes 1
s
10
–5
when nothing is input for
tol
. Also see “Integration and Differential
Calculation Precautions” and “Tips for Successful Integration Calculations”
for more information. See
8
.
: Function for approximation of the derivative based on the central
difference method. Natural Display input syntax is
dx
d
(
f
(
x
))
x
=
a
, while
Linear Display input syntax is
dx
d
(
f
(
x
),
a
,
tol
).
tol
specifies tolerance,
which becomes 1
s
–10
when nothing is input for
tol
. Also see “Integration
and Differential Calculation Precautions” for more information. See
9
.
: Function that, for a specified range of
f
(
x
), determines sum
(
f
(
x
))
x=a
b
=
f
(
a
) +
f
(
a
+1) +
f
(
a
+2) + ...+
f
(
b
). Natural Display input syntax is
(
f
(
x
))
x=a
b
,
while Linear Display input syntax is
3(
f
(
x
),
a
,
b
).
a
and
b
are integers that
can be specified within the range of –1
s
10
a
b
10
. See
10
.
Note: The following cannot be used in
f
(
x
),
a
, or
b
: Pol, Rec,
°,
d
/
dx
,
3.
Pol, Rec : Pol converts rectangular coordinates to polar coordinates, while
Rec converts polar coordinates to rectangular coordinates. See
11
.
Pol(
x
,
y
) = (
r
, θ) Rec(
r
, θ) = (
x
,
y
)
Rectangular
Polar
Coordinates (Rec)
Coordinates (Pol)
Specify the angle unit before
performing calculations.
The calculation result for
r
and θ
and for
x
and
y
are each assigned
respectively to variables X and Y.
Calculation result
Q is displayed
in the range of −180°
Q
180°.