### Matrix Entry and Matrix Addition, Scalar Multiplication on TI-83

This page is devoted to presenting, in a step by step fashion, the keystrokes and the screen images for entering matrices into the TI-83 family of calculators. In addition, this page will show editing such values and how to perform Matrix Addition, Scalar Multiplication on those matrices. The matices used in these examples are
IMPORTANT NOTE: The TI-83 uses the key to get to the MATRIX screen. The TI-83 Plus and TI-84 Plus calculators use the two key sequence to get to the MATRIX screen. The results of the calculator survey for the Fall 2010 semester are:
As a result this page will consistently use the two key sequence to demonstrate moving to the MATRIX screen. Users of tthe TI-83 will have to substitute their one key action for the two key presented here.

An almost as important note: The TI-84 Plus allows for software upgrades. The newest version of the software, version 2.53, allows for a much prettier display of matrices. If you are using the calculator with the new software you can turn off the prettier display (directions to do so are way down at Figures 60 through 65) to make following the first 60 figures a bit easier.
 Figure 1 Figure 1 demonstrates the most straight forward method for entering a matrix. The entire matrix is enclosed in square brackets, [ and ]. Each row of the matrix is also enclosed in square brackets. When entering the matrix we separate numeric values with a comma. The keystrokes to enter Figure 1 would be . Figure 2 If we now press the key, the calculator accepts our definition and displays the matrix. Note that the displayed matrix is on multiple lines, the enclosing square brackets are still there, each row is still surrounded by square brackets, but that the commas are not present. Figure 3 We want to store the matrix in one of the ten (10) defined matrices on these calculators. Those matrices have specific, given names. In particular, they are [A], [B], [C], [D], [E], [F], [G], [H], [I], and [J]. We can recall a previous entry by using the sequence. Following that we press the key to arrive at Figure 3. Figure 4 Even though we can enter square brackets and we can type letters, we cannot type the single symbol [A]. We need to move to the MATRIX menu to find that symbol. We move to Figure 4 by pressing the key sequence. [Remember, on the TI-83 there is a single MATRIX key to do this.] We ant to store this in [A], the highlighted selection, so we press the key to move to Figure 5. Figure 5 This is the entire command to define a matrix and store it in [A]. Pres to perform the command. Figure 6 Again, the calculator displays the matrix, but this time the matrix is stored in [A]. There is no indication of the fact that it is stored on this screen. Figure 7 Figure 7 shows the definition of another matrix, the one we want to store in [BD], along with the arrow indicating that we have already pressed the key. Now we want to enter the symbol [D]. To do that we need to return to the MATRIX menu. Figure 8 Having returned to the MATRIX menu, we see that the display has changed to show that [A] is defined as a 2x2 matrix. This reflects our earlier steps. However, at this point we merely want to select [D], item number 4. Figure 9 Press to insert the [D] at the end of our command and then press to perform the command and move to Figure 9. The matrix [D] is displayed as a 2 row, 3 column matrix. Figure 10 In Figure 10 we have entered the definition of the matrix originally named x in the image at the top of this web page. Notice that this is a matrix with 1 row and 4 columns. It must still be entered in the matrix form with the surrounding square brackets and the single row enclosed in square brackets. Unfrtunately, we cannot have a matrix with the name x on the TI-83 family of calculators. We are restricted to the 10 defined matrices on the calculator. Therefore, we will have to select a different name. We will assign this matrix to [J]. Figure 11 We move to the MATRIX page to find the name [J], but it is not there. You might notice that there is a downward pointing arrow after the final option number, 7, at the bottom of the screen. This indicates that there are more options. We will need to move down (or up) using the cursor keys or to find the desired name, [J]. Figure 12 In Figure 12 we have located the name [J] and highlighted its selection key, 0. We can choose the [J] entry by pressing the key. Figure 13 Figure 13 shows that the [J] matrix name was inserted in our command. We then pressed the key to perform the command. The calculator responded with a display of the matrix. Figure 14 In the previous screens we have seen a method of just typing in the matrix, giving the STORE command via the key, selecting the matrix name from the MATRIX window, and pressing to perform the command. Starting with Figure 14 we will look at another way to enter a matrix. Here, in Figure 14, we return to the MATRIX window, but this time we use the key to move to highlight the EDIT feature. Once there we use the key to highlight matrix [B], the one we will enter now usign the editor. Finally, we press the key to move to Figure 15. Figure 15 The calculator displays [B] in its current state. The top of the screen gives the current dimensions, that is, the number of rows and columns of [B]. We can change those dimensions by entering new values in this region. Figure 16 The matrix that we want to enter has 2 row and 2 columns. We press the key to indicate the 2 rows. Figure 17 Press to move to the number of columns. Notice in Figure 17 that the highlight is now on the number of columns and taht the editor has created two rows for our matrix. Figure 18 Use the key to indicate that there are two columns. Figure 19 Press the key to accpt that value. The calculator changes the display to have two rows and two columns. In addition, the calculator cursor is positioned at the first item in the matrix, ready for us to enter a value. Figure 20 The value for row 1 column 1 is 11, so we enter the value and the display changes to that shown in Figure 20. Press the to move to Figure 21. Figure 21 The calculator has accepted the value of 11 for row 1 column 1 and it has moved to the next item in the matrix. Figure 22 We pressed to put the -1 value into row 1 column 2 and then move to the next item. Figure 23 Pressing the gets us to Figure 23. Figure 24 Figure 23 completed the data entry for [B]. We can return to the MATRIX window by using the keys. Then move to the EDIT subwindow and move the highlight down to [C]. Figure 25 Press to move to the matrix edit window in Figure 25. Now we are ready to enter the dimensions, row and column, of the matrix, followed by the daa values that we want in the matrix. Figure 26 Matrix [C] has 2 rows and 3 columns. We entered those values and then the six values that fill the matrix. Figure 27 Having completed [C] in Figure 26, we return to the MATRIX window, move to the EDIT subwindow, highlight [E] so that we are redy to specify and fill [E]. Figure 28 Figure 28 shows [E] specified as 3 rows and 2 columns, and the values have been entered. But wait! There is a data entry error! The item in row 2 column 1 was entered as 2 but it needs to be -2. Figure 29 Correcting the vlaue is not a problem. We use the cursor keys to move the highlight back to row 2 column 1. Figure 30 Now we enter the correct value. It is displayed at the bottom of the screen. Figure 31 We tell the calculator to accept the new value by pressing the key. Figure 31 shows that the correction has been made. Figure 32 Figure 32 shows the data entry for [F]. Figure 33 Figure 33 shows the data entry for [G]. Figure 34 Figure 34 shows the data entry for [H]. Figure 35 Figure 35 shows the data entry for [I]. Figure 36 Returning to the MATRIX window, we see that all of our matrices, at aleast oall the ones that fit on the window, are defined.

Thus far we have seen how to get matrices into the calculator. The section below discusses matrix addition, scalar multiplication, and matrix transposition on the TI-83 family of calcualtors.