## Sequences

In the latter part of a calculus course, one begins to work with sequences and series. Sequences are simply functions whose domain is limited to integers rather than to real numbers. We illustrate with the sequence .

To work with sequences, first we need to set the graph mode to sequence. Press to access the mode menu. Highlight the Graph mode (FUNCTION is showing in the window displayed below). Press the right arrow key on the thumb pad to display the Graph menu. Select 4:SEQUENCE, then press . Finally, press again to save the mode settings.

Press to access the equation editor. Enter the sequence u1=1/(n^2+1), then press . Press F2 to access the Zoom menu, then select 6:ZoomStd to view a graph of the sequential values (below, middle screen). For a better view, press WINDOW to access the window menu. The graph below at right uses the window settings xmin = 0, xmax = 10, xscl = 1, ymin = 0, ymax = .6, yscl = .1. Then press GRAPH to view the graph.

 One may work with sequences now just like with functions. You may obtain sequential values or a table of values. For example, press HOME to return to the home screen. In the entry line, enter U to obtain u1(5); i.e., u5 .038436154.

Warning Remember to set the Graph mode back to function for doing usual calculator work.