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 to highlight the Calculate icon, then press or press 1.
Fractions and mixed numbers can be entered using and SHIFT , respectively.
To enter the calculation to the left, press:
7 8 + SHIFT 2 3 11
To change the solution to a decimal format, press .
Press SHIFT (a↔) to convert the result into a mixed-number format.
When inputting radical expressions, the radical bar automatically extends as additional characters are typed. Press 2 4 =.
The output will be displayed in simplest radical form, but can be converted into a decimal approximation by pressing .
Radical Calculations
ClassWiz is capable of recognizing and combining like radicals. Press:
2 4 + 1 5 0 =
It can also calculate unlike radicals. Press:
2 4 - 9 8 =
Higher-order radicals can be beautifully expressed using Natural Textbook Display™ input. Press:
SHIFT (x⁻¹) 5 6 4 =
Natural Textbook Display™ templates can be stacked inside one another to allow input of complicated expressions such as this quotient of rational exponentials. Press:
3 x 2 ÷ 3 x 2 =
(Note: the calculator does not generate a Syntax Error when the key is used to create a negative sign. Both and are acceptable for use.)
Trigonometry and Logarithms
In a trigonometry setting, arithmetic can be performed in terms of π. Press:
3 x 10 ( )
2 10 ( )
Other useful Natural Textbook Display™ templates that help overcome typical calculator input frustrations include: logarithms of any base,
1 ÷ 2 5 6
Summation, Derivatives, and Integrals
...summation (sigma) notation,
SHIFT ( x ² + 1 ) 3 7
...derivatives of a function at a specific point (value),
SHIFT ( 4 x ² - 5 x ) x = 0 . 2
...and definite integrals.
5 ÷ 1 2 d x
Settings for the "Calculate" mode can be accessed by pressing SHIFT MENU (SET UP).
Press one or more times to reveal additional Setup options.
Setup Options:
- 1:Input/Output
- 2:Angle Unit
- 3:Number Format
- 4:Engineer Symbol
- 1:Fraction Result
- 2:Complex
- 3:Statistics
- 4:Spreadsheet
- 1:Equation/Func
- 2:Table
- 3:Decimal Mark
- 4:Digit Separator
- 1:MultiLine Font
- 2:QR Code
- 3:Contrast
SOLVE Function
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 SHIFT CALC (SOLVE).
Solve x² + Ax + Bx = 0 for x when A = 5 and B = 6.
Enter the equation by pressing, x ² + ALPHA ( A ) + ALPHA . ( B ) ALPHA CALC 0.
Input an initial guess for x followed by the values of A and B. Press:
SHIFT CALC (SOLVE)
Arrow back up to x= and SOLVE the equation by pressing .
To accomplish the same task and solve for A or B, enter a value for x and a value for one of the other unknowns. For example, to solve for A when x = 1 and B = 4, press:
SHIFT CALC (SOLVE)
Arrow back up to A= and SOLVE the equation by pressing .
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.
ENGINEERING CALCULATIONS
There are many menus in the fx-991EX that can handle engineering calculations. The fx-991EX has the power to handle vectors, matrices, complex numbers and numerically calculates summation and even definite integrals.
From the Main Menu, use the arrow keys to highlight the Calculate icon and press or press 1.
There are many different types of unit conversions that can be accomplished on this menu. To view the options, press SHIFT 8 (CONV). Use the down arrow key to see all the possibilities.
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 press 1.
Unit Conversion Categories:
- 1: Length
- 2: Area
- 3: Volume
- 4: Mass
- 1: Velocity
- 2: Pressure
- 3: Energy
- 4: Power
- 1: Temperature
To convert 500 inches (in) into centimeters (cm), press AC to return to the initial Calculate screen.
Press 5 0 0 SHIFT 8 (CONV) 1 (Length)
Length Conversion Options:
- 1:in cm
- 2:cm in
- 3:ft m
- 4:m ft
- 5:yd m
- 6:m yd
- 7:mile km
- 8:km mile
- 9:n mile m
- A:men mile
- B:pckm
- C:km pc
Volume Conversions
To find the difference between one US Gallon and one UK Gallon, first, convert to a common unit, like a liter (L).
Press 1 SHIFT 8 (CONV) 3 (Volume)
1 (gal(US)) L
One US gallon is approximately 3.785 L.
Now, convert the solution to gallons UK. Press:
SHIFT 8 (CONV) 3 (Volume) 4
(L gal(UK))
It looks like a US gallon is smaller. 1 US gallon = 0.8326742321 UK gallons.
The same calculation can be accomplished using a string of conversions. Press:
1 SHIFT 8 (CONV) 3 (Volume)
1 (gal(US)) SHIFT 8 (CONV) 3 (Volume) 4 (L gal(UK))
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 5 x10x 9.
The gap between digits at place value separation can be viewed by entering Set Up. Press SHIFT MENU (SET UP) and use the arrow keys to navigate to the third menu.
Setup Options:
- 1:Equation/Func
- 2:Table
- 3:Decimal Mark
- 4:Digit Separator
Press 4 (Digit Separator) 1 (On) to turn on the Digit Separator to show separation between place values.
Press to recalculate the result and display clear place value separation.
To convert this solution into engineering notation, use the ENG key to change the solution into scientific notation. To move the decimal to the right, press ENG.
To move the decimal to the left, press SHIFT ENG (→).
Calculating with engineering symbols has never been easier. To turn on the engineering symbols in setup, press SHIFT MODE (SET UP).
Select 4 (Engineer Symbol) 1 (On) to turn on the Engineering Symbols.
Engineering Symbol Calculations
To calculate 500k (kilo) + 10M (Mega), press:
5 0 0 OPTN 3 (Engineering Symbols)
6 k+ 1 0 OPTN 3 (Engineering Symbols)
7 (M)
The solution is displayed using the appropriate units.
Now, use the ENG key to convert between units.
