Casio fx-115WA User manual

E
fx-115WA
fx-991WA
User’s Guide

Removing and Replacing
the Calculator’s Cover
•To Remove the cover
Grasp the top of the cover, and slide the unit out from the
bottom.
•To Replace the cover
Grasp the top of the cover, and slide the unit in from the
bottom.
Always slide the unit into the cover with the unit’s display
end first. Never slide the keyboard end of the unit into the
cover.
CASIO ELECTRONICS CO., LTD.
Unit 6, 1000 North Circular Road,
London NW2 7JD, U.K.

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Safety Precautions
Be sure to read the following safety precautions before
using this calculator. Keep this manual handy for later ref-
erence.
Caution
This symbol is used to indicate information that can
result in personal injury or material damage if ignored.
Batteries
•After removing the batteries from the calculator, put
them in a safe place where there is no danger of
them getting into the hands of small children and
accidently swallowed.
•Keep batteries out of the reach of small children. If
accidently swallowed, consult with a physician im-
mediately.
•Never charge batteries, try to take batteries apart, or
allow batteries to become shorted. Never expose bat-
teries to direct heat or dispose of them by incinera-
tion.
•Misuse of batteries can cause them to leak acid that
can cause damage to nearby items and creates the
possibility of fire and personal injury.
•Always make sure that a battery’s positive kand
negative lsides are facing correctly when you
load it into the calculator.
•Remove the batteries if you do not plan to use the
calculator for a long time.
•Use only the type of batteries specified for this cal-
culator in this manual.
Disposing of the Calculator
•Never dispose of the calculator by burning it. Doing
so can cause certain components to suddenly burst,
creating the danger of fire and personal injury.

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•The displays and illustrations (such as key markings)
shown in this User’s Guide are for illustrative pur-
poses only, and may differ somewhat from the ac-
tual items they represent.
•The contents of this manual are subject to change
without notice.
•In no event shall CASIO Computer Co., Ltd. be li-
able to anyone for special, collateral, incidental, or
consequential damages in connection with or aris-
ing out of the purchase or use of these materials.
Moreover, CASIO Computer Co., Ltd. shall not be
liable for any claim of any kind whatsoever against
the use of these materials by any other party.
Handling Precautions
•Be sure to press the key before using the cal-
culator for the first time.
•Even if the calculator is operating normally, replace
the battery at least once every three years.
Dead battery can leak, causing damage to and malfunc-
tion of the calculator. Never leave the dead battery in the
calculator.
•The battery that comes with this unit discharges
slightly during shipment and storage. Because of
this, it may require replacement sooner than the nor-
mal expected battery life.
•Low battery power can cause memory contents to
become corrupted or lost completely. Always keep
written records of all important data.
•Avoid use and storage in areas subjected to tempera-
ture extremes.
Very low temperatures can cause slow display response,
total failure of the display, and shortening of battery life.
Also avoid leaving the calculator in direct sunlight, near
a window, near a heater or anywhere else it might be-
come exposed to very high temperatures. Heat can
cause discoloration or deformation of the calculator’s
case, and damage to internal circuitry.

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•Avoid use and storage in areas subjected to large
amounts of humidity and dust.
Ta k e care never to leave the calculator where it might
be splashed by water or exposed to large amounts of
humidity or dust. Such elements can damage internal
circuitry.
•Never drop the calculator or otherwise subject it to
strong impact.
•Never twist or bend the calculator.
Avoid carrying the calculator in the pocket of your trou-
sers or other tight-fitting clothing where it might be sub-
jected to twisting or bending.
•Never try to take the calculator apart.
•Never press the keys of the calculator with a ball-point
pen or other pointed object.
•Use a soft, dry cloth to clean the exterior of the unit.
If the calculator becomes very dirty, wipe it off with a
cloth moistened in a weak solution of water and a mild
neutral household detergent. Wring out all excess mois-
ture before wiping the calculator.Never use thinner, ben-
zine or other volatile agents to clean the calculator. Do-
ing so can remove printed markings and damage the
case.

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Contents
Safety Precautions ........................................... 1
Handling Precautions ...................................... 2
Two-line Display ............................................... 5
Key Layout ........................................................ 6
Before Starting Calculations... ...................... 7
kModes .................................................................... 7
kInput Capacity ........................................................ 8
kMaking Corrections During Input ........................... 8
kReplay Function ..................................................... 8
kError Locator .......................................................... 9
kExponential Display Formats ................................. 9
kAnswer Memory ..................................................... 9
Basic Calculations ......................................... 10
Memory Calculations ..................................... 10
kIndependent Memory ........................................... 10
kVariables .............................................................. 10
Fraction Calculations .................................... 11
kFraction Calculations ............................................11
kDecimal-to-Fraction Conversion ........................... 11
kFraction-to-Decimal Conversion ........................... 11
Percentage Calculations ............................... 12
Scientific Function Calculations .................. 13
kTr igonometric/Inverse Trigonometric Functions ... 13
kHyperbolic/Inverse Hyperbolic Functions ............ 13
kAngle Unit Conversion ......................................... 14
kCommon and Natural Logarithms/
Antilogarithms ...................................................... 14
kSquare Roots, Cube Roots, Roots, Squares,
Cubes, Reciprocals, Factorials,
Random Numbers and π.......................................... 14
kFIX, SCI, RND ..................................................... 15
kENG Calculations ................................................ 16
kInputting ENG Calculation Symbols ..................... 16
kCoordinate Conversion
(Pol(x,y), Rec (r, θ )) ............ 17
kPermutation ......................................................... 18
kCombination ......................................................... 18

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Statistical Calculations .................................. 18
kStandard Deviation (SD Mode) ............................ 18
kProbability Distribution Calculations ................... 19
kRegression Calculations (REG Mode) ................. 20
Complex Number Calculations
(CMPLX Mode) ................................................ 22
kAbsolute Value/Argument Calculation ................. 23
Metric Conversions ( fx-991WA )................... 23
Scientific Constants ( fx-991WA ).................. 25
Base-nCalculations ....................................... 26
Degrees, Minutes, Seconds Calculations .... 28
Technical Information .................................... 28
kWhen you have a problem...... ............................. 28
kError Messages ................................................... 29
kOrder of Operations ............................................. 30
kStacks .................................................................. 31
kPower Supply ...................................................... 31
kInput Ranges ....................................................... 33
Specifications ................................................. 35
Two-line Display
You can simultaneously check the calculation
formula and its answer.
The first line displays the calculation formula.
The second line displays the answer.

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DT CL
M-
M
AM
µ
G
mk
pf n
BINS
ScI
McI
AB
Csin
-1
cos
-1
tan
-1
D
XY
EF
DISTR Re<->lm argrAbs
y
y
Rnd Ran#
10
e
SHIFT ALPHA MODE
REPLAY
DEC OCTHEX BIN
Key Layout
Page
Page
Page
Page
Page
Page
Page
Page
Page
Page
Page
Page
Page
Page
Page
11
8
2
15
15 25 1417 15 14
11
17
28 14 27 14 27
16 11 1514 14 14
10 28 10 1010 13 10 13 10
10 28 1313 13
19 23 23 1020 23 19 10 10 10
10 10 1010 10 1919
20 16 20 1620 16 8 10 18
8
20 16 20 1620 16 18 18
18 16 18 1618 16 20 20
15 1515 14 12
10 9
17 23
LOGIC
24
15 27
x!
T C
DRG
< fx-991WA >
ON/CLEAR
Rec(
nCr
18
18
fx-115WA:
nPr nPr
CONV
nPr nCr
CONV
Key Layout

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Before Starting Calculations...
kModes
Application Mode Mode
Name Indicator
Calculation Modes
Normal calculations COMP –
Complex number CMPLX CMPLX
calculations
Standard deviation SD SD
calculations
Regression calculations REG REG
Base-ncalculations BASE-N b (binary)
o(octal)
d(decimal)
H(hexadecimal)
Angle Unit Modes
Degrees DEG R
Radians RAD T
Grads GRA B
Display Modes
Exponential notation NORM1 –
(Canceling FIX and SCI NORM2 –
specification)
Number of decimal FIX Fix
place specification
Number of significant SCI Sci
digit specification
Exponential display range ENG ENG
specifications
Note!
•Mode indicators appear in the lower part of the display,
except for the Base-nindicators which appear in the ex-
ponent part of the display.
•The ENG mode cannot be selected while the calculator
is in the CMPLX or BASE-N mode.

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•You cannot set the angle unit or the display mode while
the calculator is in the BASE-N mode.
•The COMP, CMPLX, SD, and REG modes can be used
in combination with the angle unit modes.
•Be sure to check the current calculation mode (SD, REG,
COMP, CMPLX) and angle unit mode (DEG, RAD, GRA)
before beginning a calculation.
kInput Capacity
•The memory area used for calculation input can hold 79
“steps.” Whenever you input the 73rd step of any calcu-
lation, the cursor changes from “_” to “k” to let you know
memory is running low. If you still need to input more,
you should divide your calculation into two or more parts.
kMaking Corrections During Input
•Use eand rto move the cursor to the location you
want.
•Press [to delete the number or function at the current
cursor position.
•Press AKto change to an insert cursor t. Inputting
something while the insert cursor is on the display in-
serts the input at the insert cursor position.
•Press e, r, AK, or =returns to the normal cur-
sor from the insert cursor.
kReplay Function
•Pressing ror erecalls the last calculation you per-
formed. You can then make any changes you want in
the calculation and re-execute it.
•Pressing tdoes not clear Replay memory, so you can
recall the last calculation even after you press t.
•Replay memory is cleared whenever you start a new
calculation, change to another mode, or turn off power.