TI-92 Help -- Graphing a Sequence

To graph a sequence begin by pressing MODE to get to the MODE menu shown at the right.
The Graph option should be set to SEQUENCE . If the Graph option is set differently use the cursor pad to arrow right to see the submenu shown at the right. Now use the cursor pad to select the SEQUENCE option. Then press ENTER to set this option. Then press ENTER again to save the new option. Note: You must set the graphing mode to SEQUENCE as described above before setting the window settings as described below.
Next press green-diamond WINDOW to see the screen shown at the right. This screen allows you to set the following items. nmin -- the smallest value for n. This must be an integer >= 0. It designates the index of the first term in the sequence to be computed. It is usually 1 or 0. nmax -- the largest value for n. This must be a positive integer >= nmin. It designates the index of the last term in the sequence to be computed. plotstrt -- this indicates the first term to be plotted. Notice that the terms plotted may be different from the range of terms computed -- for example, if nmin = 1 and plotstrt = 11 the first ten terms will be computed but not plotted. plotstep -- the increment used for determining which terms are plotted. Notice that if plotstep = 2 every other term will be plotted although all the terms will be computed. xmin -- the low end of the x-axis range. xmax -- the high end of the x-axis range. xscl -- the distance between x-axis tick marks. ymin -- the low end of the y-axis range. ymax -- the high end of the y-axis range. yscl -- the distance between y-axis tick marks. xres -- the pixel resolution. Usually this is set at 2 and the calculator computes the values of the function at every other pixel along the x-axis and fills in linearly. Higher numbers produce faster but rougher graphs. When xres is set at 1, functions are evaluated at every pixel along the x-axis.
Next press Green-diamond Y= to go to the Y= menu as shown in the screen at the right. You may use this screen to describe one or more sequences. The sequences are called u1, u2, and so forth. Each sequence is described by a pair of lines as shown in the screen at the right. The first line -- something like -- u1=2.5 (1 - .001 u1(n - 1)) u1(n - 1) is called the change equation and describes how the seqeunce changes from one term to the next. Notice that the right hand side describes how to compute each term u1(n) in terms of the preceding term u1(n - 1). The second line describes the initial value of the sequence -- that is, the value of the first term.
Next while still in the Y= menu highlight the first sequence and then press F6 to go to the STYLE submenu as shown in the screen at the right. Use this submenu to select the Thick option and then press ENTER to set the option. Repeat this for each sequence -- highlighting the sequence in the F= menu and then selecting Thick using the Style submenu and ENTER .
Now press Green-diamond GRAPH to see a graph of the sequence or sequences that you specified as shown in the screen at the right.