Casio fx-991ES PLUS - Manual (Page 16)

E-15
x ! : Factorial function. See
12
.
Abs : Absolute value function. Note that the input method is different
depending upon whether you are using Natural Display or Linear Display.
See
13 .
Ran# : Generates a 3-digit pseudo random number that is less than 1.
The result is displayed as a fraction when Natural Display is selected.
See
14 .
RanInt# : For input of the function of the form RanInt#( a , b ), which generates
a random integer within the range of a to b . See 15 .
n P r , n C r : Permutation (nPr) and combination (nCr) functions. See 16 .
Rnd : The argument of this function is made a decimal value and then rounded
in accordance with the current number of display digits setting (Norm, Fix, or
Sci). With Norm 1 or Norm 2, the argument is rounded off to 10 digits. With
Fix and Sci, the argument is rounded off to the specified digit. When Fix 3
is the display digits setting, for example, the result of 10 ÷ 3 is displayed
as 3.333, while the calculator maintains a value of 3.33333333333333 (15
digits) internally for calculation. In the case of Rnd(10÷3) = 3.333 (with Fix
3), both the displayed value and the calculator’s internal value become
3.333. Because of this a series of calculations will produce different results
depending on whether Rnd is used (Rnd(10÷3)
s 3 = 9.999) or not used (10
÷ 3 s
17 .
Note: Using functions can slow down a calculation, which may delay display
of the result. Do not perform any subsequent operation while waiting for the
calculation result to appear. To interrupt an ongoing calculation before its
result appears, press
.
Integration and Differential Calculation Precautions
• Integration and differential calculations can be performed in the COMP
Mode ( ) only.
• The following cannot be used in f ( x ), a , b , or tol : Pol, Rec, °, d / dx , 3.
• When using a trigonometric function in f ( x ), specify Rad as the angle
unit.
• A smaller tol value increases precision, but it also increases calculation
time. When specifying tol , use value that is 1 s 10 –14 or greater.
Precautions for Integration Calculation Only
• Integration normally requires considerable time to perform.
• For
f ( x ) a x b (as in the case of
0
1
3 x 2 – 2 = –1), calculation
will produce a negative result.
• Depending on the content of f ( x ) and the region of integration, calculation
error that exceeds the tolerance may be generated, causing the calculator
to display an error message.
Precautions for Differential Calculation Only
• If convergence to a solution cannont be found when tol input is omitted,
the tol value will be adjusted automatically to determine the solution.
• Non-consecutive points, abrupt fluctuation, extremely large or small points,
inflection points, and the inclusion of points that cannot be differentiated,
or a differential point or differential calculation result that approaches zero
can cause poor precision or error.