CASIO

Use the MATRIX Mode to perform calculations involving matrices of up to 3 rows by 3 columns. To perform a matrix calculation, you first assign data to special matrix variables (MatA, MatB, MatC), and then use the variables in the calculation as shown in the example below.

Example 1: To assign to MatA and  to MatB, and then perform the following calculations: × (MatA×MatB), + (MatA+MatB)

1. Press (MATRIX) to enter the MATRIX Mode.

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2. Press (MatA)(2×2).
This will display the Matrix Editor for input of the elements of the 2 × 2 matrix you specified for MatA.

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• (1) "A" stands for "MatA".

3. Input the elements of MatA: 2111.

4. Perform the following key operation:
(MATRIX)(Data)(MatB)(2×2). This will display the Matrix Editor for input of the elements of the 2 × 2 matrix you specified for MatB.

5. Input the elements of MatB: 2112.

6. Press to advance to the calculation screen, and perform the first calculation (MatA×MatB):
(MATRIX)(MatA)(MATRIX)(MatB).
This will display the MatAns screen with the calculation results.

(2) "Ans" stands for "MatAns".

   Note: "MatAns" stands for "Matrix Answer Memory". See "Matrix Answer Memory" for more information.

7. Perform the next calculation (MatA+MatB):
(MATRIX)(MatA)(MATRIX)(MatB).

Matrix Answer Memory

Whenever the result of a calculation executed in the MATRIX Mode is a matrix, the MatAns screen will appear with the result. The result also will be assigned to a variable named "MatAns".
The MatAns variable can be used in calculations as described below.

To insert the MatAns variable into a calculation, perform the following key operation: (MATRIX)(MatAns).

Pressing any one of the following keys while the MatAns screen is displayed will switch automatically to the calculation screen: , , , , , , (x3). The calculation screen will show the MatAns variable followed by the operator or function for the key you pressed.

Assigning and Editing Matrix Variable Data

To assign new data to a matrix variable:

1. Press (MATRIX)(Dim), and then, on the menu that appears, select the matrix variable to which you want to assign data.

2. On the next menu that appears, select dimension (m×n).

3. Use the Matrix Editor that appears to input the elements of the matrix.

Example 2: To assign to MatC

• (MATRIX)
  (Dim)(MatC)(2×3)
  101011
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To edit the elements of a matrix variable:

1. Press (MATRIX)(Data), and then, on the menu that appears, select the matrix variable you want to edit.

2. Use the Matrix Editor that appears to edit the elements of the matrix.
Move the cursor to the cell that contains the element you want to change, input the new value, and then press .

To copy matrix variable (or MatAns) contents:

1. Use the Matrix Editor to display the matrix you want to copy.
If you want to copy MatA, for example, perform the following key operation: (MATRIX)(Data)(MatA). If you want to copy MatAns contents, perform the following to display the MatAns screen: (MATRIX)(MatAns).

2. Press (STO), and then perform one of the following key operations to specify the copy destination: (MatA), (MatB), or (MatC).
This will display the Matrix Editor with the contents of the copy destination.

Matrix Calculation Examples

The following examples use MatA = and MatB = from Example 1, and MatC = from Example 2.

Example 3: 3 × MatA (Matrix Scalar Multiplication).

• 3(MATRIX)(MatA)
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Example 4: Obtain the determinant of MatA (det(MatA)).

• (MATRIX)(det)
  (MATRIX)(MatA)
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Example 5: Obtain the transposition of MatC (Trn(MatC)).

• (MATRIX)(Trn)
  (MATRIX)(MatC)
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Example 6: Obtain the inverse matrix of MatA (MatA-1).

Note: You cannot use for this input. Use the key to input "-1".

• (MATRIX)(MatA)
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Example 7: Obtain the absolute value of each element of MatB (Abs(MatB)).

• (Abs)(MATRIX)(MatB)
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Example 8: Determine the square and cube of MatA (MatA2, MatA3).

Note: You cannot use for this input. Use to specify squaring, and (x3) to specify cubing.

• (MATRIX)(MatA)
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• (MATRIX)(MatA)(x3)
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Example 9: Determine the MatA = row echelon form.

• (MATRIX)(Ref)
  (MATRIX)(MatA)
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Example 10: Determine the MatA = reduced row echelon form.

• (MATRIX)(Rref)
  (MATRIX)(MatA)
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