# How to use a Graphing Calculator

Over the past decade, graphing calculators have become an invaluable tool in education and technology. Calculations that took hours in the past now take seconds. Children who struggle with math now have a fighting chance. Intensive investigation of graphing calculators is best, but all that is necessary is a surface understanding.

Before delving into how they are used, one should consider the different types and brands of graphing calculators that are available. While Casio and other companies offer viable options, Texas Instruments is, and has been the leader in this field for many years. Most commonly used models currently are the TI-83, TI-84, and TI-NSpire. The NSpire is the future of graphing calculators, though it has interchangeable faceplates, one allowing it to operate as a TI-84, making it the present of graphing calculators as well.

To start simply, graphing calculators can be used the same way as a scientific or four-function calculator. One major difference is the use of the “enter” button instead of the “=” button. When starting out, users may also have a hard time locating certain buttons. Fortunately, there is a catalog button which allows users to search through every function the calculator is capable of. In time, these functions will become more easily accessible. An important skill to understand at the basic level is the use of the “2nd” and “Alpha” buttons. These change what specific buttons do, based on the corresponding word or symbol above each button.

The real genius of these calculators is their ability to graph and create tables from given equations. If I had a nickel for every time I heard someone say, “That’s so cool” the first time they see a graphed function, not only would I be rich, but I could graph and chart how many nickels I had acquired over a given period of time. To be amazed, one must first press the “Y=” button. Here, there is a list from Y1 to Y10, allowing the user to graph up to ten equations at once. All that needs to be done to do so, is type the equation, keeping in mind that the variable to be used, “X” can be typed by using the variable button which contains the symbols: X, T, n, and theta. Once that is done, a press of the “graph” button will begin the magic. If the “2nd” button is pressed before the “graph” button, the calculator will instead display a table of values. The graph may look cooler, but I find the table to be more useful.

One simple and useful capability of the calculators is finding intersections. When two or more equations are graphed simultaneously, a user can calculate any and all intersections by pressing the “2nd” button followed by the “trace” button. This brings up a list of calculations. Selecting “Intersect” from this list will display the graph, along with a prompt of: “1st curve?” The user is being asked to place the cursor on the first line to be used. Next, the calculator will ask, “2nd curve?” After selecting the second, the user will be asked to “Guess?” Here, the cursor must be placed near the intersection to be determined. Once “enter” is pressed, the screen will display an X-value and a Y-value, representing the point of intersection.

Graphing Calculators are capable of so much more that the surface that has been scratched here. They are useful for elementary students through college students and beyond. The more practice and exploration, the more one learns, and the more useful they become.