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# Notation for Transformations

## Formatting of points or equations to show transformations.

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Practice Notation for Transformations
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Point Notation and Function Notation

When performing multiple transformations, it is very easy to make a small error. This is especially true when you try to do every step mentally. Point notation is a useful tool for concentrating your efforts on a single point and helps you to avoid making small mistakes.

What would  look like in point notation and why is it useful?

#### Watch This

http://www.youtube.com/watch?v=An29CALYjAA James Sousa: Function Transformations: A Summary

#### Guidance

A transformation can be written in function notation and in point notation. Function notation is very common and practical because it allows you to graph any function using the same basic thought process it takes to graph a parabola in vertex form.

Another way to graph a function is to transform each point one at a time. This method works well when a table of  values is available or easily identified from the graph.

Essentially, it takes each coordinate  and assigns a new coordinate based on the transformation.

The new  coordinate is straightforward and is directly from what takes place outside  because  is just another way to write . For example,  would have a new  coordinate of

The new  coordinate is trickier. It comes from undoing the operations that affect

For example,  would have a new  coordinate of

Example A

Convert the following transformation into function notation and point notation.  Then, apply the transformation to the three points in the table. Transformation: Horizontal shift right three units, vertical shift up 4 units.

 1 3 2 5 8 -11

Solution:

Note that the operations with the  are different. The point notation is a straightforward approach to apply the transformation.

Example B

Convert the following function notation into point notation and apply it to the included table of points.

 0 0 1 4 2 8

Solution: The  component can be directly observed. For the  component you need to undo the argument.

Note: Point notation greatly reduces the mental visualization required to keep all the transformations straight at once.

Example C

Convert the following point notation to words and to function notation and then apply the transformation to the included table of points.

 10 8 12 7 14 6

Solution: This problem is different because it seems like there is a transformation happening to the original left point. This is an added layer of challenge because the transformation of interest is just the difference between the two points. Notice that the  coordinate has simply doubled and the  coordinate has gotten bigger by one and turned negative. This problem can be rewritten as:

Concept Problem Revisited

The function  would be written in point notation as . This is useful because it becomes obvious that the  values are all divided by three and the  values all increase by 7.

#### Vocabulary

Notation is a mathematical convention that helps others read your work. It is supposed to be designed to help aid your thinking, but when misunderstood can cause great confusion.

#### Guided Practice

1. Convert the following function notation into words and then point notation. Finally, apply the transformation to three example points.

2. Convert the following function in point notation to words and then function notation.

3. Convert the following function in function notation to words and then point notation.

1.

Vertical reflection across the  axis. Vertical stretch by a factor of 2. Vertical shift 4 units. Horizontal shift right one unit.

2.

Horizontal stretch by a factor of 3 and then a horizontal shift right one unit.

Vertical reflection over the  axis and then a vertical shift 7 units up.

3.

Vertical reflection across the  axis, stretch by a factor of  and shift up 3. Horizontal shift right 1 unit.

#### Practice

Convert the following function notation into words and then point notation. Finally, apply the transformation to three example points.
 0 5 1 6 2 7

1.

2.

3.

4.

5.

Convert the following functions in point notation to function notation.

6.

7.

8.

9.

10.

Convert the following functions in function notation to point notation.

11.

12.

13.

14.

15.

### Answers for Explore More Problems

To view the Explore More answers, open this PDF file and look for section 1.3.

### Vocabulary Language: English

function notation

function notation

In the context of transformations, function notation describes how a function $f(x)$ changes as a result of the transformation.
point notation

point notation

In the context of transformations, point notation describes how each coordinate $(x,y)$ changes as a result of the transformation.