Evaluate Parametric Equations on the TI-83 Plus

You can use the TI-83 Plus graphing calculator to evaluate a pair of parametric equations at a specified value of T. To do so, following these steps:

1. Graph the equations in a viewing window that contains the specified value of T.

   To get a viewing window containing the specified value of T, that value must be between Tmin and Tmax.

2. Set the Format menu to ExprOn and CoordOn.

3. Press [2nd][TRACE] to access the Calculate menu.

4. Press [1] to select the value option.

5. Enter the specified value of T.

   To do so, use the keypad to enter the value of T. If you make a mistake when entering your number, press [CLEAR] and re-enter the number.

6. Press [ENTER].

   After you press [ENTER], the first highlighted pair of parametric equations in the Y= editor appear at the top of the screen, the cursor appears on the graph of that function at the specified value of T, and the coordinates of the cursor appear at the bottom of the screen.

7. Repeatedly press

   

   to see the value of the other graphed parametric equations at your specified value of T.

   Each time you press

   

   the names of the parametric equations being evaluated appear at the top of the screen; the coordinates of the cursor location appear at the bottom of the screen.

   

If you’re planning on evaluating parametric equations at several specified values of T, consider constructing a user-defined table.