Texas Instruments TI-82 User Manual - Page 89

Defining and Displaying a Parametric Graph Parametric equations consist of an X component and a Y component, each expressed in terms of the same independent variable T. They are often used to graph equations over time. Up to six pairs of parametric equations can be defined and graphed at a time. Defining a Parametric Graph The steps for defining a parametric graph are the same as those for defining a function graph. Differences are noted below. Setting Parametric Graph Modes Press z to display the MODE settings. To graph parametric equations, you must select Par before you enter WINDOW variables or enter the components of parametric equations. Also, you usually should select Connected to obtain a more meaningful Par graph. Displaying Parametric Equations After selecting Par MODE, press o to display the parametric Y= edit screen. On this screen, you display and enter both X and Y components. TI.82 has six equations, each defined in terms of T. Defining Parametric Equations Follow the same procedures as for Func graphing to enter the two components that define a new parametric equation. ¦ You must define both the X and Y components in a pair. ¦ The independent variable in each component is T. You may press „, rather than pressing ƒ ãTä, to enter the parametric variable T. (Par MODE defines the independent variable as T.) Parametric Graphing 4-3