QUICK START GUIDE

fx-991EX

The fx-991EX “ClassWiz” features a high-resolution
display, making it easier to view formulas and symbols.
This remarkable screen can display between 2-6 times
as many characters as other scientific calculators, yetstill runs on solar power.

Use the W key to turn the calculator on, and press
qC(OFF) to power the unit down.
The icon-based menu, accessible via the p key,
allows easy navigation of features using the arrow keys
and the number keys or the Q shortcuts.
The o key can be used like Backspace in a word
processor to delete the character(s) left of the cursor.
The symbols printed on the keys use Natural Textbook
Display™ notation, similar to that found in textbooks.
This makes input of expressions fast and easy.
The n key toggles your calculation results between
Standard (exact) and Decimal forms.

http://edu.casio.com/

The following explains the meaning of each icon on the fx-991EX icon menu
Icon

Menu Name

Description

CALCULATE

Perform general computations using Natural Textbook Display™ notation, including
absolute value, logs of any base, summation, derivatives, and integrals.

COMPLEX

Perform computations with complex numbers, including a + bi form, polar (form, and conversions between the two.

BASE-N

Perform binary, octal, and hexadecimal computations, and convert among those number
bases and base-10.

MATRIX

Perform operations on matrices up to 4x4, including matrix arithmetic,
determinants, transpositions, and identity matrices.

VECTOR

Perform operations on 2- and 3-dimensional vectors, including vector
arithmetic, dot products, angles, and unit vectors.

STATISTICS

Calculate 13 different one-variable statistics, and apply linear, quadratic,
logarithmic, exponential, and geometric (power) regressions.

DISTRIBUTION

Investigate Normal, Inverse Normal, Binomial, and Poisson probability andcumulative distributions.

SPREADSHEETCreate spreadsheets with up to 5 columns and 45 rows. Spreadsheet
supports Fill, Cut/Copy/Paste, recursive formulas, Mean, and Sum commands.

TABLE

Create tables of values to compare up to 2 functions simultaneously.

EQUATION/FUNCTION

Solve simultaneous (systems of) equations with up to 4 unknowns, andpolynomials of up to degree 4.

INEQUALITY

Solve polynomial inequalities of up to degree 4, with the solution set expressed as
a compound inequality.

RATIO

2

)

Solve proportions of the form A : B = X : D and A : B = C : X.

fx-991EX Quick Start Guide

CALCULATE
Below are some examples of the Natural Textbook Display™ input/output notation, as found by selecting the Calculate

icon from the Main Menu of the fx-991EX.
From the Main Menu, use the arrow keys tohighlight the Calculate icon, then press =or press 1.

Fractions and mixed numbers can be entered using
a and qaA, respectively.
To enter the calculation to the left, press
a7$8$+qaA2$3$
11p.
To change the solution to a decimal format,
press n.

Press qnN to convert the result intoa mixed-number format.

When inputting radical expressions, the radical bar
automatically extends as additional characters are typed.
Press s24=.

The output will be displayed in simplest radical form, but canbe converted into a decimal approximation by pressing n.

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CALCULATEClassWiz is capable of recognizing and combining like radicals.
Press s24$+s150=.

It can also calculate unlike radicals. Press
s24$-s98=.

Higher-order radicals can be beautifully expressed using
Natural Textbook Display™ input.
Press q^F5$64=.

Natural Textbook Display™ templates can be stacked
inside one another to allow input of complicatedexpressions such as this quotient of rational exponentials.
Press a3^a1$2$$$3^2=.
(Note: the calculator does not generate a Syntax Error when the - key is used to createa negative sign. Both - and z are acceptable for use.)
In a trigonometry setting, arithmetic can be performed interms of π. Press a3qKC$4$+
2qKC=.

Other useful Natural Textbook Display™ templates that help
overcome typical calculator input frustrations include:
logarithms of any base,ia1$2$$16=

4fx-991EX Quick Start Guide

CALCULATE...summation (sigma) notation,
qxIxd+1$-3$7=…derivatives of a function at a specific point (value),
qyY4xd-5x$0.2=…and definite integrals.
ya1$x$$2$5=.

Settings for the “Calculate” mode can be accessed by pressing
qp(SET UP).
Press R one or more times to reveal additional Setup options.

SOLVE
The fx-991EX can elegantly solve an equation for any unknown using Newton’s method with the SOLVE command. To
use SOLVE, first input the equation to be solved, then press qr(SOLVE).

Solve x2 + Ax + Bx = 0 for x when A = 5 and B = 6.
Enter the equation by pressing, xd+Qz(A)x+Qx(B) Qr(=)0.

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CALCULATE
Input an initial guess for x followed by the values of A and B.
Pressqr(SOLVE) -5p5p6p.

Arrow back up to x= and SOLVE the equation bypressing p.

To accomplish the same task and solve for A or B, enter avalue for x and a value for one of the other unknowns.
For example, to solve for A when x = 1 and B = 4, press
qr(SOLVE)1p2p4p.

Arrow back up to A= and SOLVE the equation bypressing p.

The solution also displays L – R = 0. This means that
Newton’s method of approximation is directly on -5. If L – R
is not 0, simply recalculate to get a better approximation.

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fx-991EX Quick Start Guide

CALCULATEENGINEERING CALCULATIONSThere are many menus in the fx-991EX that can handle engineering calculations. The fx-991EX has the power tohandle vectors, matrices, complex numbers and numerically calculatessummation and even definite integrals.
From the Main Menu, use the arrow keys to highlight the
Calculate icon and press p or press 1.

There are many different types of unit conversions that canbe accomplished on this menu. To view the options, press
q8(CONV). Use the down arrow key (R) to see all thepossibilities.
Each one of the choices has a wide range of conversion options
for many different types of unit conversion.

Use the arrow keys to locate the Length conversion and press1.

To convert 500 inches (in) into centimeters (cm), press C toreturn to the initial Calculate screen.

Press 500q8(CONV)1(Length)1(in : cm)p.

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CALCULATE
To find the difference between one US Gallon and one UK
Gallon, first, convert to a common unit, like a liter (L).
Press 1q8(CONV)3(Volume)1(gal(US) : L)p.
One US gallon is approximately 3.785 L.
Now, convert the solution to gallons UK.
Press q8(CONV)3(Volume)4(L : gal(UK))p.
It looks like a US gallon is smaller.
1 US gallon = 0.8326742321 UK gallons.

The same calculation can be accomplished using astring of conversions.
Press 1q8(CONV)3(Volume)1(gal(US) : L)q8(CONV)
3(Volume)4(L: gal(UK))p.
ENGINEERING NOTATION
Converting large numbers into scientific and engineering notations
can be accomplished through a short series of keystrokes.
Start with a large number like 2.5 X 109.
Press 2.5K9p.

The gap between digits at place value separation can be viewed
by entering Set Up. Press qp(SET UP) and use the arrow
keys to navigate to the third menu.

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fx-991EX Quick Start Guide

CALCULATE
Press 4(Digit Separator)1(On) to turn on the Digit Separator
to show separation between place values.

Press p to recalculate the result and display clear place value
separation.

To convert this solution into engineering notation, use the b
key to change the solution into scientific notation. To move thedecimal to the right, press b.

To move the decimal to the left, press qbX.

Calculating with engineering symbols has never been easier.
To turn on the engineering symbols in setup, press
qw(SET UP).

Select 4(Engineer Symbol)1(On) to turn on theEngineering Symbols.

fx-991EX Quick Start Guide

9CALCULATE
To calculate 500k (kilo) + 10M (Mega), press
500i3(Engineering Symbols)
6(k)+10i3(Engineering Symbols)
7(M)p.
The solution is displayed using the appropriate units.

Now, use the b key to convert between units.

10fx-991EX Quick Start Guide

COMPLEX
Complex Number calculations can be executed in the Complex Mode.
From the Main Menu, use the arrow keys to highlight theComplex icon, then press p or press 2.

In Complex Mode, operations can be carried out using
the imaginary unit U. To add complex numbers, press
2+3bU+5-7bUp.

Complex numbers that are multiplied are displayed incomplex format. Press (3-2bU)(5+6bU)p.

The argument of the complex number 1+2i, can be found by
taking the arctan (y/x) = 63.4349° or by using the Argumentcommand.

Press i1(Argument)1+2bU)p.

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COMPLEXCOMPLEX FORM AND POLAR FORM
To convert a complex number into polar form, press
2+5bUiR1(: r∠q)p.

To convert any polar form of a complex number, use the r theta
command or type in the angle in polar form.
Press C2qbZ330iR
2(: a+bi)p.
Alternately, simply type in the angle in polar form by pressing
2qbZ330p.

These calculations can also be accomplished in radian mode.
To change to radian mode, press qp(SET UP)2(Angle
Unit)2(Radian).

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fx-991EX Quick Start Guide

MATRIX
Operations with matrices and matrix related calculations are all located in the Matrix Menu.
From the Main Menu, use the arrow keys to highlight the Matrix
icon and press p or press 4.

To enter matrices, first, define the matrix.

Press 1(MatA)2(Rows)2(Columns)
1p2pz3p4p.

To enter a second matrix, press i.

From the resulting popup window, press 1(Define
Matrix)2(MatB).

Select the number of rows, 2(Rows).

Select the number of columns, 2(Columns).

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MATRIXEnter the matrix values by pressing
3pz6p8p2p.

To perform matrix calculations, like addition, subtraction, andmultiplication, follow these simple commands.
To enter Matrix calculation, press C.
To recall the name of a matrix, press i.
To add A + B, press 3(MatA)+i4(MatB)p.

The solution matrix is displayed in the window and can be viewed
without scrolling.

To calculate the determinant of the matrix, pressiR2(Determinant) i3(MatA))p.

Matrices can be used to solve a system of equations.
Take the following equation with 3 unknowns:

Enter the coefficient matrix as Matrix A and the solution matrix as Matrix B.
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fx-991EX Quick Start Guide

MATRIX
Redefine the matricies by pressing i1(Define Matrix).

Press 1(MatA) to define Matrix A and enter the3 x 3 coefficient matrix.

Select the number of rows, 3(Rows).

Select the number of columns, 3(Columns).

Enter the values of the coefficients, pressing p after
each one to move to the next value.

Now, enter the 3 x 1 solution matrix as Matrix B.

Press i1(Define Matrix).

Define Matrix B 2(MatB) as a 3 x 1, so select 3(Rows)
and 1(Columns) from the next two windows.

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MATRIXEnter the values of the coefficients, pressing p after each
one to move to the next value.

Press C to return to the Matrix Calculation screen.

The solution can be found by calculating A-1 x B.
Press i3(MatA)uOi4(MatB)p.

The solution represents the following:This same system can also be solved using the Equation icon.

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fx-991EX Quick Start Guide

VECTORThe fx-991EX is capable of handling vector calculations with vectors in 2 or 3 dimensions.
From the Main Menu, use the arrow keys to highlight the
Vector icon and press p or press 5.

Let vectors u and v be defined in the 3-dimensional plane by thefollowing: u = 2i + 3j – 2k and v = 3i - 4j + 5k

Define u as Vector A with dimension 3.
Press 1(VctA)3(Dimension).

Enter the components of the vector and press p after each one
to move to the next value.

Define v as Vector B with dimension 3.
Press i1(Define Vector).

Press 2(VctB)3(Dimension).

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VECTOREnter the components of the vector and press p after each
one to move to the next value.

To execute basic vector operations, press C to enter
Vector calculation.
Recall the names of the vectors and execute the desired
operation by pressing i.
Vector addition, subtractions, and multiplication are all available.
For subtraction, press 3(VctA)-i4(VctB)p.

For multiplication, pressi3(VctA)Oi4(VctB)p.

The sums of the product of the components of a vector
are known as the vector’s dot product. So,.
Press i3(VctA)iR2(Dot Product)i4(VctB)p.

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fx-991EX Quick Start Guide

VECTOREven some very complex vector operations like the angle between vectors, which is defined as
which

in

are easily accomplished on the fx-991EX.

To calculate vector cross product (not vector multiplication),press iR3(Angle)i3(VctA)q)(,)i4(VctB))p.

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STATISTICS
The fx-991EX can calculate several one-variable statistics, and also analyze relationships between two data setsusing various regression models.
From the Main Menu, use the arrow keys to highlight theStatistics icon, then press p or press 6.

On the resulting menu, select 1 for “1-Variable” statistics.

A data entry screen appears.
This example uses the following list of some students’ heights,
given in inches: 70.5, 74, 67, 71, 71, 72, 73.5, 72, 69, 71.
Enter data by typing in each value one at a time, with eachfollowed by the p key.
70.5p, 74p, etc.

To calculate the 1-Variable statistics for this data set,press i3(1-Variable Calc).

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fx-991EX Quick Start Guide

STATISTICS
13 different 1-variable statistics have been calculated, 6 of which appear on the first screen. Press R one or moretimes to reveal additional statistics:

These statistics have each been stored inside the fx-991EX as variables, in case you should wish to use them infurther calculations.
Press C to return to the data entry screen.

Enter the Option menu by pressing i.

Select item 4(Statistics Calc) to enter the Statistics
calculation area.

Press i, and then the down arrow (R) once to reveal thedifferent categories of statistical variables.

For instance, to calculate the interquartile range (IQR), press
3(Min/Max)4(Q3)-iR3(Min/Max)2(Q1)p.

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STATISTICSFREQUENCY TABLES
If the data comes from a frequency table, ClassWiz can be set up to input the data values in one column, and thefrequencies in another.
To access the set-up menu, press qp(SET UP).

Press the down arrow (R) to reach the second page and 3
to select the Statistics settings.

Press 1 to turn the Frequency option On.

The Statistics Calculation area appears again. Even thoughnothing appears to have happened, the setting has indeed
changed.

To access the Data entry area, press i3(Data).

Notice a second column for frequencies now appears andthe previous data set has been erased.

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fx-991EX Quick Start Guide

STATISTICSEnter the same 10 students’ height used previously making
use of the Frequency column. As each data point is inputted,
ClassWiz automatically assigns a default Frequency of 1. Edit aFrequency by using the arrow keys to highlight it, then typing a
new Frequency followed by p.
Once all of the data points (x) and frequencies (Freq) have beenentered, press i3(1-Variable Calc) again to display the
1-Variable statistics.

(Notice, the statistics are identical to those previously found.)REGRESSIONS
To calculate a linear regression, pressi i1(Select Type).

Select option 2(y=a+bx).

A reminder that changing the type of statistics will clear previous
data appears.
Press p to confirm and Clear memory.

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STATISTICS
Two columns for pairwise data (ordered pairs) now appears.
Note, the Frequency (Freq) column still appears; press
qp(SET UP)R3(Statistics)2(Off)to remove it.
Input the ordered pairs (1, 1), (2, 4), (3, 9), and (4, 16). Use thearrow keys to navigate to the “y” column as necessary.

To view 2-Variable statistics or the linear regression results,
press i3.

The 2-Variable statistics display calculation results for both x and y:

Press Ci4(Regression Calc) to display the linear
regression results.

Other regressions, including quadratic, logarithmic, exponential,
and geometric, can be accessed via i1(Select Type).

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fx-991EX Quick Start Guide

DISTRIBUTION
The fx-991EX can quickly generate probability distribution tables, covering the Normal, Inverse Normal, Binomial, andPoisson distributions.
From the Main Menu, use the arrow keys to highlight theDistribution icon, then press por press 7.

Several distribution choices appear. Use R to access the second page.

Select 1(Binomial CD) from the second page to analyze thefollowing Binomial Distribution problem: “A fair 6-sided die isrolled six times. Find P(6 comes up at least twice).”

To enter the values of x (number of successes), N (number oftrials), and p (probability of success), press 2(Variable). Input
the values as shown, using a to create the fraction separator.

After pressing p to input the value of p, ClassWiz
automatically converts the fraction into a decimal for its
own purposes.
Press p again to calculate the probability.

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DISTRIBUTION
A probability of 73.7% is displayed.
Because x = 1 was entered, the calculator calculated P(≤ 1 six isrolled). This provides a great opportunity to use the complementof an event: P = 1 – 0.737 = 0.263 = 26.3%.
To display the probabilities of obtaining any number of sixes in 6
rolls, press i1(Select Type).

This time, choose 4(Binomial PD).

Because the calculation is for probabilities for several different
numbers of successes, select 1(List).

Enter the values 0, 1, 2, 3, 4, 5, and 6 into the “x” column (which
represents number of successes). Press p after each input.

Once the final value has been entered, press p again to end
the data entry process.

Notice, the values of N and p are preserved from the cumulative
probability calculation.(N and p are global calculator variables.)26

fx-991EX Quick Start Guide

DISTRIBUTION
Press p one more time to calculate the probability
distribution table.

Notice how the small probabilities are expressed in proper
scientific notation!

INVERSE NORMAL
To calculate an Inverse Normal Distribution, pressi1(Select Type).
(“Editor” edits the previous PD’s data list.)
Select 3(Inverse Normal).

Input the values as shown to answer the question: “If the heights
of U.S. males are normally distributed with a mean of 70 inches
and a standard deviation of 4 inches, what range defines thetallest 10% of U.S. males?”Press p once more to reveal the result. To be in the top 10%
of U.S. males by height, a man must be over 75 inches (6’3”) tall.

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SPREADSHEETThe Spreadsheet mode is useful for studying the statistics of data that require more than two lists. It also supports
recursive formulas, sequences, and series.
From the Main Menu, use the arrow keys to highlight the
Spreadsheet icon, then press por press 8.

The ClassWiz spreadsheet looks and acts similarly to many
popular software spreadsheet applications.

Investigate the mass of different common sizes of laundry
detergent bottles, when the average density of liquid laundry
detergent is 0.885 g/mL. Type 0.885p incell A1.
Use the arrow keys to move over to cell B1, and input
40p to represent a 40 fl oz. (1 fl oz. = 29.5735 mL)bottle of laundry detergent.

Move to cell C1, and press Qr(=) to create an equals
sign. Like in other spreadsheet programs, this is the first stepnecessary when entering a formula.

To “grab” the value within a cell, press i2(Grab).

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fx-991EX Quick Start Guide

SPREADSHEETNavigate to cell B1, and press p (Set) to Grab the value in thatcell.

This places a reference to cell B1 within the formula.

To create a conversion from fluid ounces (fl oz.) to milliliters (mL),type O29.5735p.

The formula has correctly calculated that a 40 fl oz. bottle oflaundry detergent has a volume of 1182.9 mL.
Formulas can also be typed directly, without using the Grab
command.
Navigate to cell D1 and input Qr(=)
Qz(A)1OQu(C)1p.

A 40 fl oz. (1182.9 mL) bottle of laundry detergent
has a mass of 1046.9 grams.

Now, let’s use the power of relational formulas to check someother bottle sizes:
To populate many different cells with the same value, pressi2(Fill Value).
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SPREADSHEET
Input the density of laundry detergent as the Value andA2:A6 as the cell Range. Press Qz(A)2Qy(:)
Qz(A)6pp.

Column A is now filled with the density value.
Next populate column B with additional bottle sizes.
Navigate to cell B2, and input the value 75 by pressing
75p.

To populate many different cells with the same formula,press i1(Fill Formula).

Input the formula Qx(B)2+25p.

Notice, the cell Range is pre-populated with the currently
highlighted cell (B3).
Use the right arrow to edit only the end cell by pressing$$$$$$o6pp.
Scroll down to cell B6 to make sure that the formula has beenadjusted relative to each cell’s position, so that cells B2 to B6 now
display bottle sizes from 75 to 175 fl oz. (1 fl oz. = 29.5735 mL).

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fx-991EX Quick Start Guide

SPREADSHEETNavigate to cell C1, which still displays the formula used toconvert fluid ounces to milliliters.

The ClassWiz has a “copy and paste” option that can be usedinstead of retyping the same formula repeatedly.
Press iR2(Copy & Paste).
The formula from the currently highlighted cell (C1) has now
been copied.
Scroll down one cell at a time (Rp) to Paste this formula
into cells C2 through C6.
Column C now contains the volumes, in milliliters, of the different
sizes of laundry detergent bottles.
To exit Copy & Paste mode, press C.

Time to practice! Use the same technique to Copy & Paste themass calculation formula from cell D1 into cells D2 through D6.

If done correctly, Column D should show masses (in grams) as
shown.
So, for example, a 175 fl oz. (5175.3 mL) bottle of laundry
detergent has a mass of about 4.5 kg.
A decent amount of data has been entered now. To checkhow much free space remains in ClassWiz’s memory, pressi4(Free Space).

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SPREADSHEET
1318 Bytes of memory remain as free space.
Numerical values require 10 Bytes each, while formulas require
17+ Bytes each.
Determine the average capacity of the different bottles of laundry
detergent.
Navigate to cell B7, and press i.
Scroll down three pages (RRR), and select 3(Mean).

Type in the cell range of the average Qx(B)1Qy(:)
Qx(B)6)p.

The average capacity is 110.83 fluid ounces.

If one of each of these bottles was purchased, what is the total
weight of laundry detergent purchased that would be placed ina car?

Navigate to cell D7, and press i.
Return again to the summary statistics calculation screen(RRR) and select 4(Sum).

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fx-991EX Quick Start Guide

SPREADSHEETUse the Grab command rather than typing the locations of thecells in the cell range.

Press i2(Grab).

Scroll up to cell D1, and Set it as the object to be Grabbed bypressing p.

Use Qy(:) to type a colon.

Grab cell D6 as the ending cell in the cell range by pressing
i2Ep.

Close the parentheses ()), and press p to calculate the sumof the masses in cells D1 through D6.

The bottles would have a total mass of 17404 grams, or about
17.4 kilograms.
But this is a mass, not a weight!

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SPREADSHEETThis is one example of the powerful ways in which various
features of the fx-991EX can be combined.
Begin entering the formula as shown into cell D8 by pressing
Qr(=)Qj(D)7.
Press q8(CONV) to access the Conversion menu.
Select 4(Mass).

Choose mass conversion 4(kg:lb).

This will convert the mass from cell D7, which is currently in
kilograms, into pounds.

Press p, and Voila!
Even ClassWiz’s powerful Conversion feature can be used within
the Spreadsheet module. But wait… 38 thousand pounds?!?
17404 grams needs to be converted into kilograms.
With cell D8 highlighted, press i3(Edit Cell).

A cursor appears in the previously entered formula, allowing it to
be edited.

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fx-991EX Quick Start Guide

SPREADSHEETUse the right arrow key ($) to move within the formula,inserting parentheses and a factor-of-1000 adjustment asshown. Press $($$P1000)p.

Phew! That’s better. The car is no longer carrying 19+ tons oflaundry detergent home. The actual total weight is a much morereasonable 38 pounds.

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TABLEThe Table feature on the fx-991EX is a powerful way to solve a single function or two functions simultaneously.
The table range and step is easily customizable.
From the Main Menu, use the arrow keys to highlight the Table
icon and press p or press 9.

To change the setup of the table to generate a table with only one
function, press qp(SET UP).

Use the down arrow key to view the menu option for Table; itwill be the 3rd screen.
Press 2(Table) to choose the number of functions used in
the table.

Press 1(f(x)) to generate a table with only one function as
an input.

Consider the classic volume of a box problem. What is the maximum volume of a box made from a 20x15 sheet ofcardboard by removing squares from each corner?
The function that represents the volume of the box isf(x)= x(20-x)(15-x).

To enter this function, press x(20-x)(15-x)p.

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fx-991EX Quick Start GuideTABLETo set the range from 1 to 7 and the step at 1, press
1p7p1p.

Press p to view the table.
Use the arrow keys to scroll through the values.

The maximum value appears to be between 5 and 6.

To refine the search, enter a new value in any place in the table.

For example, at line 8, press 6.5p.
To enter a value one-step greater than the previous value,press +.
To enter a value one-step less than the previous value,press -.
To change the step value or change the start and end values of
the table, press Cp.
Enter the new values and press p to view the table.
Use the arrow keys to scroll to the value that gives the
maximum volume.

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TABLEThe maximum volume calculated to one decimal place appears
at 5.7 inches.

Consider the following two functions.

Find the roots of the equations and points of intersection, as well as
the end behavior of each function.
Press qp(SET UP) and use the down arrow key to viewthe menu option for Table. Press 2(Table) to choose thenumber of functions used in the table.

Press 2(f(x),g(x)) to generate a table with two function as
inputs.

Enter the first function as f(x) by pressing x^3$7x+6p.
If there is already a function present, press C
to clear the previous function.
Enter the second function as g(x) by pressing xd3x+2p.

Create a table that has a domain of -5 to 5 with step of 1.

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fx-991EX Quick Start GuideTABLE
Press p to view the table.
Based on the information from the table, it appears f(x) goes tonegative infinity to the left and g(x) goes to positive infinity to theleft.
There appears to be roots of 1 and 2 for both functions.
To determine the behavior between roots, type in a number
between 1 and 2, like 1.5.
The right end behavior for both functions appears to be
increasing towards positive infinity.

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EQUATION/FUNC
The fx-991EX numerically solves equations elegantly. It is accomplished with the help of the Natural Textbook
Display™ in the Equation/Func mode. The Equation/Func mode uses Newton’s method to find solutions to equations.
The fx-991EX has the power to handle Simultaneous Equations with up to 4 unknowns and Polynomial Equations up
to the 4th degree.
SIMULTANEOUS EQUATIONS
From the Main Menu, use the arrow keys to highlight theEquation/Func icon and press p or press z(A).

To solve the following system of simultaneous equations,
select 1(Simul Equation).
Choose the number of Unknowns. For this example,
press 2(Unknowns).

A 2x2 system of equations template is displayed. The template isin Ax + BY = C form in which A, B and C can be any value. For
fractional values, use the a key.

Type in each value followed by the p key.
Press 2p1p, etc.

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fx-991EX Quick Start GuideEQUATION/FUNC
To solve, press p and use the arrow keys (RE) to toggle
between solutions.

The solutions are shown in natural display format. For decimal
approximations, press n.

To change the values in the system of equations withoutchanging the type of equation or system, press C.

To change the type of equation or system size, press i and select from the on-screen menus.

The fx-991EX also solves inconsistent systems, both
independent and dependent. Enter the displayed inconsistentand independent system

Press p to see the solution.

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EQUATION/FUNC
Enter the displayed inconsistent dependent system.

Press p to see the solution.

To input a larger system of simultaneous equation,press i1(Simul Equation)3(Unknowns).

Enter the coefficents for each equation and press p to solve.

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fx-991EX Quick Start GuideEQUATION/FUNC
POLYNOMIAL EQUATIONS
The fx-991EX has the computing power to solve polynomial equations up to 4th degree.
To start solving polynomial equations, in the Equation/Func icon,press i2(Polynomial).

Select the degree of the polynomial. For this example, use a
3rd degree polynomial. Press 3(Degree).

Fill out the template for a 3rd degree polynomial. Type in eachcoefficient followed by the p key.
x3 + 4x2 +x – 6 = 0
Press p to solve the equation.

Use the arrow keys (ER) to toggle through the solutions.

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EQUATION/FUNC
The fx-991EX has the power to solve polynomials in the complex plane.
Press i and change the type of polynomial toquadratic (2).

Enter the coefficients that appear in the displayed screen into
the quadratic template, and press p.

The solutions are displayed in simplified radical form including
the imaginary unit.

Press R to see the second imaginary solution.

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fx-991EX Quick Start Guide

INEQUALITY
Solving polynomial inequalities has never been easier.
From the Main Menu, use the arrow keys to highlight theInequality icon and press por press x(B).

Enter the degree of the polynomial inequality, in this case,3(Degree).

Choose the form of the inequality. Press 2().

Enter the coefficients of the polynomial, as shown.
Press 1p4p1pz6p.

Press p to see the solutions.
Notice, the form of the inequality is written
as x < a, b < x < c.
If the solution runs off the screen, use the left and right (!$)
arrow keys to see the entire solution.

fx-991EX Quick Start Guide

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NOTES

46

fx-991EX Quick Start Guide

NOTES

fx-991EX Quick Start Guide47

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fx-991EX Quick Start Guide