 This video provides step-by-step instructions on how to enter recursive equations into the TI-83 or TI-84 calculator. We recommend that you follow along on your own calculator as you view this video. Let us begin on the home screen as shown. Select Mode and scroll down to the fourth line where Function, Parametric, Polar, Sequence appears. Scroll over to Sequence and press Enter. This now puts the calculator in Sequence Mode. Now select Y equals and you will see the screen shown. As you see, there are three functions available, U, V, and W. Notice the term N min. This represents the value for which you are setting N to begin. So, if you choose to represent the initial value of your system as A sub 0, then you want to set N min to 0. Notice that U of N min appears below U of N. When we are writing recursive equations by hand, we typically start with writing the initial condition followed by the general term. Since it is different in the calculator, it is worth noting this to students and reminding them to be careful when they enter their equations. Consider the recursive system D sub 0 equals 20 and D sub N equals 1.15 D sub N minus 1. We will enter this system into U of N min and U of N. Scrolling to U of N min, we type 20. Notice that when you press Enter, the calculator automatically places curly brackets around the number. Now notice that to type U, we will use the 7 key. We type 2nd 7 to get U. Since we are in Sequence Mode, we type the X key to obtain N. So, for U of N, we type 1.15 2nd 7 parentheses N minus 1 closed parentheses. Now that we have entered these equations, we can examine the recursive system using a table of values or using a graph. Let us graph this system. We first want to look at our window to ensure that we view an appropriate graph. So select window. We see that the current setting has N min as 0, which is what we chose in the Y equals screen. So we will leave it there. We will keep N max at 10 to view 10 iterations after the initial value. Plot start and plot step are both references to the value of N. The points we want to actually plot on the screen are determined by these values. We will set plot start and plot step each to be 1 for our system. We want the plot to include each value of the system, every iteration. Note that plot step cannot be a decimal number. It must be a whole number. Now we want to choose an appropriate window to view our plot. Notice that X here actually represents N, so we will set the X min and X max values to match our N values. For our system, we will set Y min and Y max to values that will capture all of the values of the system for the first 10 iterations. We will set them to 0 and 100 respectively. Now we press graph and are able to view the plot on the screen as you see here. If you press trace, you will see the general term of the system in the top left corner. You can use the left and right arrow keys to move among the data points. Let us now look at the data in table form. We begin by pressing second window. This brings us to the table set screen. Since we want to view the table beginning from the initial value, we will set table start at 0 since this is an N value. The next line refers to the interval between each new N value that we would like to view. Since we want to see each successive iteration, we will set delta table to 1. We now type second graph for the table view. Here we see the table of values with the first column displaying N values and the second column displaying U of N. Technology is a useful aid in studying recursion. With the calculator, we can easily look at the long term behavior of a recursive system and explore how changes to our equations affect such behavior.