Matrix: Direct Entry to TI-83/84

Figure 01	We will start by making sure that this calculator is in the CLASSIC mode. Press the key to get the sidplay in Figure 01. [Note that if you are using a TI-83 or TI-83 Plus or a TI-84 Plus that does not have the next at the bottom of the screen then you can just skip to Figure 03 because you have no choice but to be in CLASSIc display mode. Use the repetedly to move to the next at the bottom of the screen. This will produce the image in Figure 02.
Figure 02	On this calculator we are indeed in CLASSIC mode, inicated by the highlight in . If the black highlight had been on the MATHPRINT option, as in then we would have moved the blinking cursor to the right, using the key to change the blinking item to cover the CLASSIC option, and then we would have pressed the key to make that the selected option. That is the status shown in the display in Figure 02. Leave Figure 02 by the sequence .
Figure 03	To directly enter a matrix the TI calculators ask us to use the [ character to signal both the start of the matrix and the start of a row. Then the ] character is used to signal the end of a row and the eend of the matrix. Values inside a row are separated with a comma. Therefore, the command to create our matrix A is [[2,3,7][5,1,6]] and the keystrokes to do this would be . That creates the image shown in Figure 03.
Figure 04	Press to have the calculator perform the command. The result is shown in Figure 04. Note how that result mimics the characters that we used to input the matrix. We can see the two rows and 3 columns, and the values in the matrix are aligned. The commas have disappeared.
Figure 05	For Figure 05 we have typed the keys needed for the second matrix. You might note that this matrix requires more keystrokes than did the first one. In fact, as we see in Figure 05, the calculator automatically, in this display mode, wraps our command onto a new line. Once we have finished typing the command we press to have the calculator process the command and produce Figure 06.
Figure 06	Here we see the new matrix. It is important to note that we have created these matrices but they have not been "stored" in a variable. In fact, having created the second one, shown in Figure 06, we have lost the first. We need to save these matrices in the variables that the calculator provides to hold such entities.
Figure 07	We start, in Figure 07 by creating the matrix and then adding, via the key, the symbol to store the new value. However, now we must find the specific variable [B]. As tempting as it might be, we cannot just type those characters. Instead we need to open the MATRIX menu via the keystrokes . This show take us to Figure 08. [Note:it is rare to find someone using a a TI-83 (not the 83 Plus) anymore. But if you have an old TI-83 then the keys are sightly different. On that calculator you open the matrix menu shown in Figure 08 via the single key.]
Figure 08	The MATRIX menu opens, as shown in Figure 08, with the start of the list of names for the ten (10) defined matrix variables. The first name is highlighted. To select the highlighted name we could press the "Enter" key or press the number key of the item. We do not want the highlighted item here so we will press to move the highlight to the second item as shown in Figure 09.
Figure 09	Now that the desired [B] is selected we press to actually choose that item. [In fact, we could use the alternative of just pressing the "2" key, and we could have done that without having the item selected.]
Figure 10	All that our last action did was to paste the name of the matrix, [B] at the end of the command that we have constructed. That actually completes the command so we can just press to have the calculator process the command.
Figure 11	For Figure 11 we have gone through similar steps of creating the matrix [A].
Figure 12	If we return to the matrix menu, via , we can see the fruits of our labor. The screen shows tha the two matrices [A] and [B] have been assigned values and that the former is a 2 x 3 matrix while the latter is a 3 x 2 matrix.
Figure 13	We wo want to look at the different effects of using the alternative display option. We use the key to return to the MODE menu and then repeatedly use the to move to that menu's second page. There we change the display option to MATHPRINT, as in the portion shown in Figure 13.
Figure 14	We will start entering the command to create our first matrix. Figure 14 shows that unfinished command. At this point we cannot see any difference from what we did in the CLASSIC mode. However, when we type the next character, ], we begin to see in Figure 15, the different working of the MATHPRINT option.
Figure 15	Notice in Figure 15 that the second to last ] has indeed been added to the command, but that the command has started to slide off the left end of the screen. MATHPRINT will keep our commands on a single line.
Figure 16	We complete the cmmand, as shown in Figure 16, and we continue to see that the command stays on one line. To have the calculator perform the command we press the key to move to Figure 17.
Figure 17	In Figure 17 we see two more changes attributable to the MATHPRINT option. The first is that our command has been recorded and replaced by . The second is that the matrix now looks more line a matrix with just the single set of large square brackets enclosing the rectangualr array of values, as in . Also in Figure 17 we have entered the command to create and store the second matrix. Once there we can press the key to havve the calculator perform that command. The result is shown in Figure 18. by
Figure 18	Here we see the transformed command and the result in nice matrix form.