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Homework Help: Transformations of functions

  1. Sep 20, 2011 #1
    I did the problem but I just need to make sure I did it correctly.. If I did it incorrectly, please let me know.

    1. The problem statement, all variables and given/known data

    Page 1: http://i55.tinypic.com/25sosgp.jpg (Zoom in)

    Page 2: http://i52.tinypic.com/ofyds5.jpg (Zoom in)

    2. Relevant equations

    Problem 4 a-d

    3. The attempt at a solution

    You can see it on the picture.
  2. jcsd
  3. Sep 20, 2011 #2


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    Homework Helper

    I don't think your parts (c) and (d) are appropriate.

    For f(x+1) you gave the point (-3, 1) because indeed f(-3+1) = f(-2), which was given.

    but for f(3x) you gave (-6, 1) however f(3*-6) = f(-18) which you don't know?
    Similarly part (d) doesn't work out either.
  4. Sep 20, 2011 #3
    Then part (b) should be wrong also. I did the same approach for part (c) and (d).

    Can you explain how I got the the Point A coordinates (0, 3/2) on part (a) on the last column? It was already done in the book for Point A of part (a) only.

    I also made the graph of these coordinates and it's moving/shifting the right way like it's supposed to, I think.
  5. Sep 20, 2011 #4


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    You might think you did the same thing, but you didn't

    When you did f(x+1), you didn't add one to the x value, you subtracted one - because after you put it through (x+1) the 1 is added back on - ie if x = -3, then f(-3+1) = f(-2) which you know.

    However, when you did f(3x) you still multiplied by 3 ??? your said x = -6. But if x = -6, f(3x) means f(-18) which you don't know. You should have divided by 3.

    Part d you also didn't do the inverse to x either.

    you were using y = 1/2 * f(x+1) so it is not surprising that a 3 became a 3/2
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