1. Introduction
This manual provides detailed instructions for the proper use and maintenance of your Casio FX-991ARX Scientific Calculator. Designed for academic and professional environments, this calculator offers a wide range of functions for various mathematical and scientific computations. Please read this manual thoroughly to ensure optimal performance and longevity of your device.
The Casio FX-991ARX is a scientific calculator featuring a Full Dot Matrix display and is powered by both battery and solar energy, ensuring reliable operation.
2. Product Overview
Figure 2.1: Front View of the Calculator. This image displays the front of the Casio FX-991ARX scientific calculator, highlighting its Full Dot Matrix display, alphanumeric keypad, and solar panel. The layout includes function keys, numeric keys, and navigation buttons.
Figure 2.2: Back View of the Calculator. This image shows the rear side of the Casio FX-991ARX calculator, featuring the battery compartment cover and anti-slip feet. The Casio brand name is embossed on the back casing.
2.1 Key Components
- Display: Full Dot Matrix display for clear representation of equations, graphs, and results.
- Keypad: Ergonomically designed keys for numerical input, scientific functions, and menu navigation.
- Solar Panel: Assists in powering the calculator in well-lit environments.
- Battery Compartment: Located on the back, housing the backup battery.
3. Initial Setup
3.1 Power Source
The Casio FX-991ARX operates on a dual power system: solar power and a single A-type battery (included). The solar panel provides power in sufficient light, while the battery ensures operation in low-light conditions or when solar power is insufficient.
3.2 Battery Installation
- Ensure the calculator is turned off.
- Locate the battery compartment cover on the back of the calculator (refer to Figure 2.2).
- Using a small screwdriver, carefully remove the screw securing the cover.
- Remove the cover and insert the A-type battery, ensuring correct polarity (+/-).
- Replace the cover and secure it with the screw.
3.3 Turning On/Off
- To turn on the calculator, press the [ON] key.
- To turn off the calculator, press [SHIFT] then [AC] (OFF).
3.4 Initial Settings
Upon first use or after a reset, you may need to adjust basic settings:
- Contrast: Press [SHIFT] then [MENU/SETUP], navigate to 'Contrast', and adjust using the arrow keys.
- Angle Unit: Press [SHIFT] then [MENU/SETUP], navigate to 'Angle Unit', and select Deg (degrees), Rad (radians), or Gra (gradians).
4. Basic Operations
4.1 Arithmetic Calculations
Enter numbers and operators in sequence. Press [=] to obtain the result.
Example: 5 + 3 x 2 = 11
4.2 Inputting Expressions
The calculator allows natural input of expressions as they appear in textbooks. Use parentheses [(] and [)] to define calculation order.
4.3 Correction and Deletion
- Press [DEL] to delete the character at the cursor position.
- Press [AC] to clear the entire calculation and reset the display.
5. Scientific Functions
The FX-991ARX provides a comprehensive set of scientific functions. Most functions are accessed directly or by pressing [SHIFT] or [ALPHA] followed by the desired key.
5.1 Common Functions
- Trigonometric: [sin], [cos], [tan] and their inverse functions ([SHIFT] + sin/cos/tan).
- Logarithmic: [log] (base 10), [ln] (natural logarithm).
- Powers and Roots: [x²], [x³], [√], [³√], [x^y].
5.2 Constants and Conversions
Access a library of scientific constants and unit conversions by pressing [SHIFT] + [CONST] or [SHIFT] + [CONV] respectively, then selecting the desired option from the menu.
5.3 Memory Functions
Store and recall values using the memory keys:
- Store: [STO] followed by a memory variable (A-F, X, Y, M).
- Recall: [RCL] followed by a memory variable.
6. Advanced Features
6.1 Equation Solving
The calculator can solve various types of equations. Access the Equation mode via [MENU]. Follow the on-screen prompts to input coefficients and variables. Note that specific equation types and variable handling may vary; refer to the on-screen instructions for detailed guidance.
6.2 Statistical Calculations
Enter Statistical mode from the [MENU] to perform calculations such as mean, standard deviation, and regression analysis. Input data and select the desired statistical calculation.
6.3 Matrix and Vector Calculations
The FX-991ARX supports matrix and vector operations. Select the appropriate mode from [MENU] to define matrices/vectors, perform additions, subtractions, multiplications, and other related calculations.
6.4 QR Code Function
The calculator includes a QR Code function. Press [SHIFT] + [QR] to generate a QR code for certain calculation results or data, which can then be scanned by a smart device for further analysis or visualization.
7. Maintenance and Care
7.1 Cleaning
Wipe the calculator with a soft, dry cloth. For stubborn dirt, dampen the cloth slightly with water and a mild detergent, then wipe dry. Avoid using harsh chemicals, solvents, or abrasive cleaners.
7.2 Storage
Store the calculator in a cool, dry place away from direct sunlight, extreme temperatures, and high humidity. Keep it in its protective case when not in use to prevent scratches and damage.
7.3 Battery Replacement
When the display becomes dim or calculations are incorrect, it may be time to replace the battery. Follow the battery installation steps in Section 3.2. Ensure to use the correct battery type (A-type).
8. Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| Calculator does not turn on. | Insufficient light for solar power, dead battery, or incorrect battery installation. | Move to a brighter area, replace the battery, or check battery polarity. |
| Display is dim or difficult to read. | Low battery, insufficient light, or contrast setting is too low. | Replace battery, move to brighter area, or adjust display contrast (Section 3.4). |
| "Syntax Error" message appears. | Incorrect mathematical expression input. | Review the entered expression for errors in syntax, such as unmatched parentheses or incorrect function arguments. |
| "Math Error" message appears. | Result exceeds calculation range, division by zero, or invalid input for a function (e.g., square root of a negative number). | Check input values and calculation range. Avoid operations like division by zero. |
8.1 Resetting the Calculator
If the calculator behaves abnormally or freezes, a reset may resolve the issue. Press [SHIFT] then [9] (CLR), then select 'All' to clear all memory and settings. This will return the calculator to its factory default state.
9. Specifications
| Feature | Specification |
|---|---|
| Product Type | Scientific Calculator |
| Model Name | FX-991ARX |
| Color | Black |
| Display Type | Full Dot Matrix LCD |
| Screen Size | 2.51 Centimeters (Visible screen diagonal: 1" / 3 cm) |
| Power Source | Battery/Solar Powered |
| Battery Type | 1 A battery (included) |
| Material | Plastic |
| Product Dimensions (L x W x H) | 16.2 x 7.7 x 1.1 cm |
| Item Weight | 170 g |
| Manufacturer | Casio |
Figure 9.1: Calculator Dimensions. This image illustrates the approximate dimensions of the Casio FX-991ARX calculator, showing a length of 6.9 inches (17 cm).
10. Warranty and Support
For warranty information and customer support, please refer to the documentation included with your product or visit the official Casio website. Casio provides support for product inquiries, technical assistance, and service requests.
