The same function using different transformation orders

Choose different valid orders by adjusting the translation.

  • Different orders can produce the same graph, but the translation usually needs to change.
  • Check the intermediate functions and the final positions of corresponding points.

Example 1

Stretch first

Produce by stretching first.

−8−7−6−5−4−3−2−11234567891011121314−7−6−5−4−3−2−11234567xyA(−4, 0)B(0, 0)C(6, 0)A′(1, 0)B′(3, 0)C′(6, 0)Original y=f(x)Final image
  1. 1.Stretch parallel to the -axis by scale factor .

  2. 2.Translate by .

Halve the -coordinates, then add 3. The result is .

Example 2

Translate first

Produce the same function , but translate first.

−8−7−6−5−4−3−2−11234567891011121314−7−6−5−4−3−2−11234567xyA(−4, 0)B(0, 0)C(6, 0)A′(1, 0)B′(3, 0)C′(6, 0)Original y=f(x)Final image
  1. 1.Translate by .

  2. 2.Stretch parallel to the -axis by scale factor .

Move 6 right, then halve the -coordinates. The result is again . A 3-right move before the stretch would give .

Remember
If you move the translation earlier, account for how the later stretch or reflection will change it.

Your turn

5 practice questions
Question 1

For , describe one sequence with the horizontal stretch first and another with the translation first. Check the image of .

Check answer
Stretch first: Stretch parallel to the -axis by scale factor . Then Translate by .Translate first: Translate by . Then Stretch parallel to the -axis by scale factor .Both give , with .

Horizontal operations act on the current -coordinates; vertical operations act on the current -coordinates.

Question 2

For , describe one sequence with the horizontal stretch first and another with the translation first. Check the image of .

Check answer
Stretch first: Stretch parallel to the -axis by scale factor . Then Translate by .Translate first: Translate by . Then Stretch parallel to the -axis by scale factor .Both give , with .

Horizontal operations act on the current -coordinates; vertical operations act on the current -coordinates.

Question 3

For , describe one sequence with the horizontal stretch first and another with the translation first. Check the image of .

Check answer
Stretch first: Stretch parallel to the -axis by scale factor . Then Translate by .Translate first: Translate by . Then Stretch parallel to the -axis by scale factor .Both give , with .

Horizontal operations act on the current -coordinates; vertical operations act on the current -coordinates.

Question 4

For , describe one sequence with the horizontal stretch first and another with the translation first. Check the image of .

Check answer
Stretch first: Stretch parallel to the -axis by scale factor . Then Translate by .Translate first: Translate by . Then Stretch parallel to the -axis by scale factor .Both give , with .

Horizontal operations act on the current -coordinates; vertical operations act on the current -coordinates.

Question 5

For , describe one sequence with the horizontal stretch first and another with the translation first. Check the image of .

Check answer
Stretch first: Stretch parallel to the -axis by scale factor . Then Translate by .Translate first: Translate by . Then Stretch parallel to the -axis by scale factor .Both give , with .

Horizontal operations act on the current -coordinates; vertical operations act on the current -coordinates.