To use the matrix function on the Casio FX 991MS calculator, you primarily need to enter the matrix mode, define the dimensions of your matrices, and input their elements. This setup allows you to perform various matrix calculations.
Entering Matrix Mode
Before you can work with matrices, you must switch the calculator to Matrix Mode.
- Press the MODE key multiple times until you see "MAT" on the display.
- Press the corresponding number key to select MAT (usually 6).
The calculator display will now show "MAT" to indicate that you are in Matrix Mode.
Defining Matrix Dimensions and Inputting Elements
Once in Matrix Mode, you can define up to three matrices: MatA, MatB, and MatC. The provided reference illustrates the steps for defining MatA and MatB.
Let's break down the process based on the reference:
1. Define MatA:
- Press the SHIFT key, then the 4 key (which has "MAT" written above it). This accesses the Matrix menu.
- Select DIM (Dimension) by pressing the corresponding number key (usually 1).
- Select the matrix you want to define, in this case, A (press the corresponding number key, usually 1).
- The calculator will prompt for dimensions (m x n, where m is rows and n is columns). As per the reference, input the dimensions: press 2 (for rows), then the = key, press 2 (for columns), then the = key. The display should show "MatA(2x2)".
2. Input Elements for MatA:
- After defining the dimensions, the calculator automatically enters element input mode for MatA.
- Input each element followed by the = key. The reference gives the elements 2 1 1 1.
- Input: 2 (=), 1 (=), 1 (=), 1 (=). The cursor will move to the next element after each input.
3. Define MatB:
- Press SHIFT then 4 (MAT) again.
- Select DIM (1).
- Select matrix B (press the corresponding number key, usually 2).
- Input the dimensions as shown in the reference: press 2 (=), then 2 (=). The display shows "MatB(2x2)".
4. Input Elements for MatB:
- Input the elements for MatB (2 1 1 2) from the reference:
- Input: 2 (=), 1 (=), 1 (=), 2 (=).
You can follow a similar process to define MatC if needed.
Accessing Defined Matrices for Calculations
After defining matrices, you can perform operations.
- To recall a defined matrix (e.g., MatA) for calculation, press SHIFT then 4 (MAT).
- Select MAT (usually 3), then select the matrix you want (e.g., A for MatA, usually 1). The display will show "MatA".
- You can then use mathematical operators (+, -, x) between matrices, or perform other matrix operations available in the MAT menu (like determinant, transpose, inverse) by selecting the appropriate options after pressing SHIFT + 4.
Here's a summary table for key actions:
| Action | Key Presses | Notes |
|---|---|---|
| Enter Matrix Mode | MODE -> Select MAT | Usually key 6 |
| Access Matrix Menu | SHIFT + 4 (MAT) | Needed for Dim, Edit, Mat, Det, Trn |
| Define Dimensions (e.g., MatA) | SHIFT + 4 -> 1 (DIM) -> Select Matrix (e.g., 1 for A) -> Input Rows (=) Input Cols (=) | Used to set size before inputting elements |
| Input Elements | After defining dimensions | Enter value -> (=) for each element |
| Recall Matrix (e.g., MatA) | SHIFT + 4 -> 3 (MAT) -> Select Matrix (e.g., 1 for A) | Use for calculations like MatA + MatB |
By following these steps, you can effectively use the matrix capabilities of your Casio FX 991MS calculator for defining and preparing matrices for operations.
