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ОглавлениеChapter 4
Graphing and Transforming Functions
You can graph functions fairly handily using a graphing calculator, but you’ll be frustrated using this technology if you don’t have a good idea of what you’ll find and where you’ll find it. You need to have a fairly good idea of how high or how low and how far left and right the graph extends. You get information on these aspects of a graph from the intercepts (where the curve crosses the axes), from any asymptotes (in rational functions), and, of course, from the domain and range of the function. A good working knowledge of the characteristics of different types of functions goes a long way toward making your graphing experience a success.
Another way of graphing functions is to recognize any transformations performed on basic function definitions. Just sliding a graph to the left or right or flipping the graph over a line is a lot easier than starting from scratch.
The Problems You’ll Work On
In this chapter, you’ll work with function graphs in the following ways:
Graphing both a function and its inverse
Determining the vertices of quadratic functions (parabolas)
Recognizing the limits of some radical functions when graphing
Pointing out the top or bottom point of an absolute-value function graph to establish its range
Solving polynomial equations for intercepts
Writing equations of the asymptotes of rational functions
Using function transformations to quickly graph variations on functions
What to Watch Out For
When graphing functions, your challenges include the following:
Taking advantage of alternate formats of function equations (slope-intercept form, factored polynomial or rational functions, and so on)
Determining whether a parabola opens upward or downward and how steeply
Graphing radical functions with odd-numbered roots and recognizing the unlimited domain
Recognizing when polynomial functions don’t cross the x-axis at an intercept
Using asymptotes correctly as a guide in graphing
Reflecting functions vertically or horizontally, depending on the function transformation
Functions and Their Inverses
181–190 Find the inverse of the function. Then graph both the function and its inverse.
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Sketching Quadratic Functions from Their Equations
191–195 Sketch the graph of the quadratic function.
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Writing Equations from Graphs of Parabolas
196–200 Given the graph of a quadratic function, write its function equation in vertex form, .
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Illustration by Thomson Digital
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Illustration by Thomson Digital
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Illustration by Thomson Digital
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Illustration by Thomson Digital
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Illustration by Thomson Digital
Investigating and Graphing Radical Functions
201–210 Identify the domain of the radical function and any intercepts. Then sketch a graph of the function.
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Investigating Absolute Value Functions
211–215 Find the range of the absolute value function. Then sketch the function’s graph.
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Investigating the Graphs of Polynomial Functions
216–223 Determine the intercepts of the graph of the polynomial. Then sketch the graph.
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Investigating Rational Functions
224–230 Determine any asymptotes of the rational function. Then graph the function.
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Transformation of Functions
231–235 Describe the transformations from the f function to the g function.
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Transforming Selected Points Using Functions
236–240 Transform the points (3, 4), (–2, 6), and (5, –1) using the function description of the transformations.
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Sketching Graphs Using Basic Functions and Transformations
241–245 Find the vertex of the given function, which is a transformation of . Then sketch the graph of the new function.
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Sketching More Graphs Using Basic Functions and Transformations
246–250 Find the vertical asymptote of the given function, which is a transformation of . Then sketch the graph of the new function.
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