# Copyright © 2011 Pearson Education, Inc. Slide 2.3-1 2.3 Vertical Stretching Vertical Stretching of the Graph of a Function If a point lies on the graph.

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Copyright © 2011 Pearson Education, Inc. Slide 2.3-1 2.3 Vertical Stretching Vertical Stretching of the Graph of a Function If a point lies on the graph of then the point lies on the graph of If then the graph of is a vertical stretching of the graph of by applying a factor of c.

Copyright © 2011 Pearson Education, Inc. Slide 2.3-2 2.3 Vertical Shrinking Vertical Shrinking of the Graph of a Function If a point lies on the graph of then the point lies on the graph of If then the graph of is a vertical shrinking of the graph of by applying a factor of c.

Copyright © 2011 Pearson Education, Inc. Slide 2.3-3 2.3 Horizontal Stretching and Shrinking Horizontal Stretching and Shrinking of the Graph of a Function If a point lies on the graph of then the point lies on the graph of (a)If then the graph of is a horizontal stretching of the graph of (b) If then the graph of is a horizontal shrinking of the graph of

Copyright © 2011 Pearson Education, Inc. Slide 2.3-4 2.3 Reflecting Across an Axis Reflecting the Graph of a Function Across an Axis For a function defined by the following are true. (a) the graph of is a reflection of the graph of f across the x-axis. (b) the graph of is a reflection of the graph of f across the y-axis.

Copyright © 2011 Pearson Education, Inc. Slide 2.3-5 2.3 Example of Reflection Given the graph of sketch the graph of (a) (b) Solution (a) (b)

Copyright © 2011 Pearson Education, Inc. Slide 2.3-6 2.3 Combining Transformations of Graphs Example Describe how the graph of can be obtained by transforming the graph of Sketch its graph. Solution Since the basic graph is the vertex of the parabola is shifted right 4 units. Since the coefficient of is –3, the graph is stretched vertically by a factor of 3 and then reflected across the x- axis. The constant +5 indicates the vertex shifts up 5 units. shift 4 units right shift 5 units up vertical stretch by a factor of 3 reflect across the x-axis

Copyright © 2011 Pearson Education, Inc. Slide 2.3-7 Graphs:

Copyright © 2011 Pearson Education, Inc. Slide 2.3-8 2.3 Caution in Translations of Graphs The order in which transformations are made can be important. Changing the order of a stretch and shift can result in a different equation and graph. –For example, the graph of is obtained by first stretching the graph of by a factor of 2, and then translating 3 units upward. –The graph of is obtained by first translating horizontally 3 units to the left, and then stretching by a factor of 2.

Copyright © 2011 Pearson Education, Inc. Slide 2.3-9 2.3 Transformations on a Calculator- Generated Graph Example The figures show two views of the graph and another graph illustrating a combination of transformations. Find the equation of the transformed graph. Solution The first view indicates the lowest point is (3,–2), a shift 3 units to the right and 2 units down. The second view shows the point (4,1) on the graph of the transformation. Thus, the slope of the ray is Thus, the equation of the transformed graph is First ViewSecond View

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