Problem:
Using the TI-85 graphing calculator, graph the triangle whose vertices are:

(1, 3), (3, 0) and (-2, -3)

Use parametric equations to draw the sides of the triangle.


Visualization:


[Press here to see animation again!]

  1. If you are not familiar with the graphing of functions on the TI-85, then first read the Initial Setup page from Little's Basic Guide to the TI-85.
  2. In order to graph a system of parametric equations, the calculator must be in the PARAM graphing mode. To change into this mode, press 2nd MODE. You should see a screen similar to the following:

  3. Using the arrow keys, move the blinking cursor to the PARAM item of the fifth row and press the ENTER key.
  4. Press the EXIT key.
  5. Press the GRAPH key and then pick E(t)= by pressing the F1 key.
  6. If necessary, keep pressing F4 key until only the two items xt1= and yt1= appear on the screen.
  7. At the prompt xt1=, type in

    1 + 2t

    and press the ENTER key.

  8. At the prompt yt1=, type in

    3 - 3t

    and press the ENTER key.

  9. At the prompt xt1=, type in

    3 - 5t

    and press the ENTER key.

  10. At the prompt yt1=, type in

    - 3t

    and press the ENTER key.

  11. At the prompt xt1=, type in

    -2 + 3t

    and press the ENTER key.

  12. At the prompt yt1=, type in

    -3 + 6t

    and press the ENTER key.

  13. The range settings for the graph above are

  14. Pick the item GRAPH from the menu by pressing the F5 key.