A vertical stretch multiplies all y-values of a function by the same factor greater than 1. A vertical compression reduces all y-values of a function by the same factor between 0 and 1. For a function f(x) and a constant a, y = af(x) is a vertical stretch when
The table below represents the function f(x). What are corresponding values of g(x) and possible graphs for the transformation
Step 1 Multiply each value of f(x) by 3 to find each corresponding value of g(x).
x | f(x) | 3f(x) | g(x) |
---|---|---|---|
|
2 | 3(2) | 6 |
|
2 | 3(2) | 6 |
0 |
|
|
|
3 | 1 | 3(1) | 3 |
5 |
|
|
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Is this a vertical stretch or compression?
3 is greater than 1, so this is a vertical stretch.
Step 2 Use the values from the table in Step 1. Draw simple graphs for f(x) and g(x).
x | f(x) |
---|---|
|
2 |
|
2 |
0 |
|
3 | 1 |
5 |
|
Vertical Translations | Horizontal Translations |
---|---|
Translation up k units,
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Translation right h units,
|
|
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Translation down k units,
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Translation left h units,
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|
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Vertical Stretches and Compressions | Reflections |
Vertical stretch,
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In the x-axis |
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Vertical compression,
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In the y-axis |
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