Keystrokes for Reflections about the x- axis

This lesson uses a graphing calculator to reflect coordinates about the x-axis.

Materials- Graphing calculator. (TI-83)

  1. Use the following example to demonstrate to the students the procedure of

reflecting ordered pairs about the y-axis on a graphing calculator.

(3 , 1), (3 , 6), (6 , 9), (7 , 7), (7 , 10), (8 , 10), (8 , 6), (8 , 1), and (3 , 1).

  1. Enter the ordered pairs of A and B into L1 and L2 on the calculator.Keystrokes for TI-83

-Press STAT and then ENTER. [If there are numbers already in L1 and L2, clear them.] To clear the lists, highlight upward on the name of the list (L1 or L2) and then press CLEAR and ENTER. Once lists are cleared, enter the x- coordinates into L1 and the y- coordinates of the ordered pairs into L2.

  1. To graph the ordered pairs, make sure all the other graphs are turned off.

Keystrokes for TI-83

-Press Y= on the first row and press CLEAR until all graphs have been

cleared.

  1. The stat plots must be cleared.

Keystrokes for TI-83

-Press 2ND and Y= and then scroll down to number 4 “Plotsoff” and press

ENTER twice until it says “done”.

  1. Graph the ordered pairs.

Keystrokes for TI-83

-Press 2NDand Y=, then press ENTER.

-Scroll over to the “ON” and then press ENTER until the “ON” is highlighted.

-Scroll down to type and choose the 2nd type of graph and then press ENTER until it is the only graph type highlighted.

-Scroll down to the Xlist and enter L1. (Press 2nd and 1)

-Scroll down to the Ylist and enter L2. (Press 2nd and 2)

-Scroll down to Mark and choose the 1st option.

  1. Enter the reflection.

Keystrokes for TI-83

-Press STAT and ENTER.

-Go to L3. [If there are numbers already in L3 and L4, clear them.] To clear the lists, highlight upward on the name of the list (L3 or L4) and then press CLEAR and ENTER.

-To enter the reflection about the y-axis the ordered pairs (x, y) will become (x, -y).

- Highlight L3 name at the top and press ENTER.

-Press 2ND, 1, and ENTER.

-Highlight L4 name at the top and press ENTER.

-Press the (-), 2ND, 2, and ENTER.

  1. To see the graph of the reflection.

Keystrokes for TI-83

-Press 2NDand Y= and then scroll down to Plot 2 and press ENTER.

-Scroll over to the “ON” and then press ENTER until the “ON” is highlighted.

-Scroll down to type and choose the 2nd type of graph and then press ENTER until it is the only graph type highlighted.

-Scroll down to the Xlist and enter L3. (Press 2nd and 3)

-Scroll down to the Ylist and enter L4. (Press 2nd and 4)

-Scroll down to Mark and choose the 2nd option.

-Press ZOOM and 9.

8. Assign worksheet on reflection to be done in a similar manner.

Keystrokes Reflections about the y- axis

This lesson uses a graphing calculator to reflect coordinates about the y-axis.

Materials- Graphing calculator. (TI-83)

  1. Use the following example to demonstrate to the students the procedure of

reflecting ordered pairs about the y-axis on a graphing calculator.

(3 , 1), (3 , 6), (6 , 9), (7 , 7), (7 , 10), (8 , 10), (8 , 6), (8 , 1), and (3 , 1).

  1. Enter the ordered pairs of A and B into L1 and L2 one the calculator.Keystrokes for TI-83
  2. Press STAT and then ENTER. [If there are numbers already in L1 and L2, clear them.] To clear the lists, highlight upward on the name of the list (L1 or L2) and then press CLEAR and ENTER. Once list are cleared, enter the x- coordinates into L1 and the y- coordinates of the ordered pairs into L2.
  1. To graph the ordered pairs, make sure all the other graphs are turned off.

Keystrokes for TI-83

  1. Press Y= on the first row and press CLEAR until all graphs have been

cleared.

  1. The stat plots must be cleared.

Keystrokes for TI-83

  1. Press 2ND and Y= and then scroll down to number 4 “Plotsoff” and press

ENTER twice until it says “done”.

  1. Graph the ordered pairs.

Keystrokes for TI-83

  1. Press 2NDand Y=, then press ENTER.
  2. Scroll over to the “ON” and then press ENTER until the “ON” is highlighted.
  3. Scroll down to type and choose the 2nd type of graph and then press ENTER until it is the only graph type highlighted.
  4. Scroll down to the Xlist and enter L1. (Press 2nd and 1)
  5. Scroll down to the Ylist and enter L2. (Press 2nd and 2)
  6. Scroll down to Mark and choose the 1st option.
  1. Enter the reflection.

Keystrokes for TI-83

  1. Press STAT and ENTER.
  2. Go to L3. [If there are numbers already in L3 and L4, clear them.] To clear the lists, highlight upward on the name of the list (L3 or L4) and then press CLEAR and ENTER.
  3. To enter the reflection about the y-axis the ordered pairs (x, y) will become (-x, y).

- Highlight L3 name at the top and press ENTER.

  1. Press the (-), 2ND, 1, and ENTER.
  2. Highlight L4 name at the top and press ENTER.
  3. Press 2ND, 2, and ENTER.
  1. To see the graph of the reflection.

Keystrokes for TI-83

  1. Press 2NDand Y= and then scroll down to Plot 2 and press ENTER.
  2. Scroll over to the “ON” and then press ENTER until the “ON” is highlighted.
  3. Scroll down to type and choose the 2nd type of graph and then press ENTER until it is the only graph type highlighted.
  4. Scroll down to the Xlist and enter L3. (Press 2nd and 3)
  5. Scroll down to the Ylist and enter L4. (Press 2nd and 4)
  6. Scroll down to Mark and choose the 2nd option.
  7. Press ZOOM and 9.

8. Assign worksheet on reflection to be done in a similar manner.