How to Put Infinity in Calculator Fx-991ex

Introduction

The Casio FX-991EX calculator is a powerful scientific calculator that supports advanced mathematical operations. When working with limits, series, or functions that approach infinity, you need to know how to properly represent infinity in your calculations.

There are three primary methods to input infinity on the FX-991EX:

1. Using the dedicated infinity key
2. Using division by zero
3. Using the infinity function

Each method has its own use cases and limitations, which we'll explore in detail.

Method 1: Using the Infinity Key

The most straightforward method is to use the dedicated infinity key on the calculator's keypad.

1. Locate the "∞" (infinity) key on your calculator. It's typically found in the function (F) or shift mode.
2. Press the "∞" key to input infinity directly into your calculation.
3. Use infinity in your equations as needed.

This method is ideal when you need to explicitly represent infinity in your calculations, such as when working with limits or series that approach infinity.

Method 2: Using Division by Zero

Another way to represent infinity is by performing division by zero. This method is useful when you need to calculate limits or evaluate expressions that approach infinity.

1. Enter a large number (e.g., 1 followed by several zeros).
2. Press the division (÷) key.
3. Enter a very small number (e.g., 0.0000000001).
4. Press the equals (=) key to see the result, which will display as infinity (∞).

This method is particularly useful when you need to simulate infinity in calculations where exact infinity isn't available as a direct input.

Method 3: Using the Infinity Function

Some advanced calculations may require using the infinity function, which is available in the calculator's function menu.

1. Press the "F" key to access the function menu.
2. Navigate to the "inf" function (this may vary by firmware version).
3. Press the "inf" function key to insert the infinity symbol (∞) into your calculation.
4. Complete your calculation as needed.

This method is useful when you need to use infinity in complex calculations or when working with functions that require infinity as an input.

Verification

To ensure that you've correctly input infinity on your FX-991EX calculator, follow these verification steps:

1. Perform a simple calculation using infinity (e.g., ∞ + 1).
2. Check that the calculator displays the correct result (∞).
3. Try different operations with infinity to confirm consistent behavior.

If the calculator doesn't recognize infinity or produces unexpected results, double-check your input method and ensure that your calculator's firmware is up to date.