This document discusses various types of graphical transformations, including translations, reflections, stretches, and shrinks. It provides examples of applying each type of transformation to graphs and finding the equations that result. Key points covered include translating graphs vertically or horizontally by adding or subtracting values, reflecting graphs across the x-axis or y-axis, stretching or shrinking graphs by multiplying values, and combining multiple transformations in sequence to transform one graph into another.
2. What youll learn about
Transformations
Vertical and Horizontal Translations
Reflections Across Axes
Vertical and Horizontal Stretches and Shrinks
Combining Transformations
and why
Studying transformations will help you to understand
the relationships between graphs that have similarities
but are not the same.
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3. Transformations
In this section we relate graphs using
transformations, which are functions that map
real numbers to real numbers.
Rigid transformations, which leave the size and
shape of a graph unchanged, include horizontal
translations, vertical translations, reflections, or
any combination of these.
Nonrigid transformations, which generally
distort the shape of a graph, include horizontal or
vertical stretches and shrinks.
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4. Vertical and Horizontal Translations
Let c be a positive real number. Then the following
transformations result in translations of the graph of
y = f(x).
Horizontal Translations
y = f(x c) a translation to the right by c units
y = f(x + c) a translation to the left by c units
Vertical Translations
y = f(x) + c a translation up by c units
y = f(x) c a translation down by c units
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5. Example Vertical Translations
Describe how the graph of f (x) x can
be transformed to the graph of y x 4.
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6. Solution
Describe how the graph of f (x) x can
be transformed to the graph of y x 4.
It is a translation
down by 4 units.
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7. Example Finding Equations for
Translations
Each view shows the graph of y1 x3 and a vertical
or horizontal translation y2 . Write an equation for y2 .
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8. Solution
Each view shows the graph of y1 x3 and a vertical
or horizontal translation y2 . Write an equation for y2 .
(a) y2 x3 3 (b) y2 x 23
(c) y2 x 33
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9. Reflections
The following transformations result in
reflections of the graph of y = f(x):
Across the x-axis
y = f(x)
Across the y-axis
y = f(x)
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10. Graphing Absolute Value Compositions
Given the graph of y = f(x),
the graph y = |f(x)| can be obtained by reflecting
the portion of the graph below the x-axis across the
x-axis, leaving the portion above the x-axis
unchanged;
the graph of y = f(|x|) can be obtained by replacing
the portion of the graph to the left of the y-axis by a
reflection of the portion to the right of the y-axis
across the y-axis, leaving the portion to the right of
the y-axis unchanged. (The result will show even
symmetry.)
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11. Stretches and Shrinks
Let c be a positive real number. Then the following
transformations result in stretches or shrinks of the
graph of y f (x):
Horizontal Stretches or Shrinks
y f
x
c
a stretch by a factor of c if c 1
a shrink by a factor of c if c 1
Vertical Stretches or Shrinks
y c f (x)
a stretch by a factor of c if c 1
a shrink by a factor of c if c 1
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12. Example Finding Equations for
Stretches and Shrinks
Let C1 be the curve defined by y1 x3 3. Find equations
for the following non-rigid transformations of C1 :
(a) C2 is a vertical stretch of C1 by a factor of 4.
(b) C3 is a horizontal shrink of C1 by a factor of 1/3.
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13. Solution
Let C1 be the curve defined by y1 x3 3. Find equations
for the following non-rigid transformations of C1 :
(a) C2 is a vertical stretch of C1 by a factor of 4.
(b) C3 is a horizontal shrink of C1 by a factor of 1/3.
(a) y2 4 f (x)
4(x3 3)
4x3 12
(b) y3 f
x
1 / 3
f (3x)
(3x)3 3
27x3 3
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14. Example Combining
Transformations in Order
The graph of y x2 undergoes the following
transformations, in order.
Find the equation of the graph that results.
a horizontal shift 5 units to the left
a vertical stretch by a factor of 3
a vertical translation 4 units up
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15. Solution
The graph of y x2 undergoes the following
transformations, in order.
Find the equation of the graph that results.
a horizontal shift 5 units to the left
a vertical stretch by a factor of 3
a vertical translation 4 units up
x2 x 52
3x 52
3x 52
4
Expanding the final expression: y 3x2 30x 79
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16. Example Combining
Transformations in Order
Describe how to transform the graph of y f x
shown to the graph of y f x 2 4.
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17. Solution
Describe how to transform the graph of y f x
shown to the graph of y f x 2 4.
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18. Solution (continued)
Describe how to transform the graph of y f x
shown to the graph of y f x 2 4.
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19. Quick Review
Write the expression as a binomial squared.
1. x2 4x 4
2. x2 2x 1
3. 4x2 36x 81
Perform the indicated operations and simplify.
4. (x 1)2 (x 1) 2
5. (x 1)3 (x 1) 2
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20. Quick Review Solutions
Write the expression as a binomial squared.
1. x2 4x 4 (x 2)2
2. x2 2x 1 (x 1)2
3. 4x2 36x 81 (2x 9)2
Perform the indicated operations and simplify.
4. (x 1)2 (x 1) 2 x2 x 2
5. (x 1)3 (x 1) 2 x3 3x2 4x
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