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Precalculus

Enter and multiply matrices

Store the matrix [[1, 2], [3, 4]] and multiply it by itself.

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A matrix is a grid of numbers. To multiply two matrices, each entry of the answer is a row of the first times a column of the second.

Here A = [[1, 2], [3, 4]] and A × A = [[7, 10], [15, 22]]. For example the top-left entry is 1×1 + 2×3 = 7.

Classic Graphing 84

Start on the main screen: Press 2nd then mode (QUIT) to get back to the home screen. Pressing clear on a menu also backs out of it.

  1. Type the matrix with the square brackets (2nd then × and − give [ and ]) and store it in [A] (sto, then 2nd x⁻¹ and 1).

    2nd[×2nd[×1,22nd]−2nd[×3,42nd]−2nd]−sto→2ndMATRIXx⁻¹1enter

  2. Type [A] twice in a row and press enter.

    2ndMATRIXx⁻¹12ndMATRIXx⁻¹1enter

You should see[[ 7 10] [15 22]]

Classic Graphing 84 key reference · Classic Graphing 84 manual

Natural Scientific 991

Start on the main screen: Press MENU, then 1 (Calculate) to return to the main calculation screen. AC clears the line you are on.

  1. Open the Matrix app (MENU, then 4). Use OPTN, 1 to define, pick MatA, then 2 rows and 2 columns. Type 1 = 2 = 3 = 4 =.

    MENU4OPTN11221=2=3=4=

  2. Use OPTN, 3 to insert MatA, then x² and =.

    OPTN3x²=

You should see[[ 7 10] [15 22]]

Natural Scientific 991 key reference · Natural Scientific 991 manual

Natural Color Graphing

Start on the main screen: Press MENU then 1 to open Run-Matrix, the main calculation screen. Press EXIT to back out of a bar or screen, and SHIFT then EXIT (QUIT) to return to the app start.

  1. On the Run-Matrix screen press F3 for MAT. Pick Mat A, make it 2 × 2, and fill in 1, 2, 3, 4 (EXE after each). EXIT twice.

    F3EXE▼▼EXE1EXE2EXE3EXE4EXEEXITEXIT

  2. Press OPTN, F2 (MAT), F1 for Mat A, then ×, then Mat A again, and EXE.

    OPTNF2F1×OPTNF2F1EXE

You should see[[ 7 10] [15 22]]

Natural Color Graphing key reference · Natural Color Graphing manual

Classic CAS

Start on the main screen: Press home to open the Home menu (Calculator, Graphs, Settings, and more). Choose Calculator, or press esc to go back to the calculation page.

  1. Open a square bracket with ctrl and (, then type 1, 2 and use ctrl and the comma for the row break (a semicolon). Finish with 3, 4 and ctrl and ).

    ctrl[(1,2ctrl;,3,4ctrl])

  2. Press x² and enter to multiply it by itself.

    x²enter

You should see[[7,10][15,22]]

Classic CAS key reference · Classic CAS manual

RPN Advanced 42

Start on the main screen: Press EXIT (once or twice) to close any menu and return to the plain stack view of Y and X.

  1. Make a 2 × 2 matrix: 2 ENTER 2, then shift and 9 (MATRIX), the first menu key (NEW), then the last (EDIT). Type 1, 2, 3, 4 using the ▶ menu key between values (the fifth menu key), then EXIT.

    2ENTER2⇧MATRIX9Σ+XEQ1LN2LN3LN4EXIT

  2. Press ENTER to copy it, then × to multiply. Open EDIT to look at the first entry.

    ENTER×XEQ

You should see1:1=7.0000

RPN Advanced 42 key reference · RPN Advanced 42 manual

RPN Power 48

Start on the main screen: Press ON to cancel what you are typing, then use the stack view. Open the MODE or VAR menu any time; the stack is always shown above the menu row.

  1. Type the matrix: left shift 9 twice for [[ ]], then 1 SPC 2. Use the right arrow twice to leave the row, SPC, left shift 9, then 3 SPC 4 and ENTER.

    ◀[ ]9◀[ ]91SPC2▶▶SPC◀[ ]93SPC4ENTER

  2. Press ENTER to copy it, then ×.

    ENTER×

You should see[[ 7 10 ] [ 15 22 ]]

RPN Power 48 key reference · RPN Power 48 manual

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