Texas Instruments TI-84 PLUS SILV Guidebook - Page 101

Defining and Editing Parametric Equations To define or edit a parametric equation, follow the steps in Chapter 3 for defining a function or editing a function. The independent variable in a parametric equation is T. In parametric graphing mode, you can enter the parametric variable T in either of two ways. • Press „. • Press ƒ [T]. Two components, X and Y, define a single parametric equation. You must define both of them. Selecting and Deselecting Parametric Equations The TI-84 Plus graphs only the selected parametric equations. In the Y= editor, a parametric equation is selected when the = signs of both the X and Y components are highlighted. You may select any or all of the equations X1T and Y1T through X6T and Y6T. To change the selection status, move the cursor onto the = sign of either the X or Y component and press Í. The status of both the X and Y components is changed. Setting Window Variables To display the window variable values, press p. These variables define the viewing window. The values below are defaults for parametric graphing in Radian angle mode. Tmin=0 Tmax=6.2831853... Tstep=.1308996... Xmin=L10 Xmax=10 Xscl=1 Ymin=L10 Ymax=10 Yscl=1 Smallest T value to evaluate Largest T value to evaluate (2p) T value increment (pà24) Smallest X value to be displayed Largest X value to be displayed Spacing between the X tick marks Smallest Y value to be displayed Largest Y value to be displayed Spacing between the Y tick marks Note: To ensure that sufficient points are plotted, you may want to change the T window variables. Setting the Graph Format To display the current graph format settings, press y .. Chapter 3 describes the format settings in detail. The other graphing modes share these format settings; Seq graphing mode has an additional axes format setting. Chapter 4: Parametric Graphing 94