Graphing Features

The TI-83 calculator offers a powerful collection of tools for exploring and analyzing graphs of equations or plots of data points. Properties like

What is the largest value of a function and where does this largest value occur;
When is an equation equal to zero;
When is one equation equal to (or bigger than) another; and
What are the general trends of a given function;

are easy to see from a graph, and the calculator has build-in commands to help explore these and many more features of graphs. The main graphing features of the TI-83 are accessed through the five graphing keys, [Y=], [WINDOW], [ZOOM], [TRACE], and [GRAPH] (and their [2^nd] functions). These keys are blue and located just below the display screen. Here’s a brief explanation of the features that are available through each of these keys.

[Y=]: This is where you enter formulas to be plotted, choose which equations to display, and control the style (thin, thick, dotted, etc.) of each equation.

[WINDOW]: From this screen, you select a range of x and y values (typically called the graphing or viewing window) which you would like to include in the plot. Tick marks, for both the x and y-axis, are also defined here.

[ZOOM]: The zoom menu gives you several options for quickly or automatically selecting useful viewing windows. You can get close-up or far-away views, automatically select y-values which fit your chosen x-values, and quickly select a standard window, to name a few of the many useful possibilities.

[TRACE]: Pressing the [TRACE] button activates a cursor (which looks like a spider) that walks along, or traces the graph. Movement of the cursor is controlled through the arrow keys. The left and right arrow keys move you along the current graph, while the up and down arrow keys allow you to jump from one function to another.

[GRAPH]: Press this button to display a plot, which incorporates the settings you have selected through the other graphing keys.

[2^nd][STAT PLOT]: Offers several useful options for displaying plots associated with statistical data.

[2^nd][TBLSET]: Values of the equations listed under the [Y=] screen and data points stored in lists can be viewed in tabular format. This screen allows you to control the set-up of the table. From this screen, you can designate-automatic or self selected inputs and outputs; where to start the table of values; and how large the steps between entries in the table should be.

[2^nd][FORMAT]: You control whether or not the calculator displays axes, coordinates of the cursor, a grid of the defined tick marks, labels for the axes and a formula for the current equation through this screen.

[2^nd][CALC]: The calculate menu gives you access to several powerful commands including: finding the value of the current equation at any x-value in the current window; locating coordinates where the functions are equal to zero, largest, or smallest; and finding places where two equations intersect or cross.

[2^nd][TABLE]: Pressing this key instructs the calculator to display the table of values defined by the settings selected from the other graphing screens.

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