Chapter 8: Problem 5
Describe each function as a transformation of the graph of the parent function \(y=\frac{1}{x}\). Then sketch a graph of each function and list values that are not part of the domain. a. \(y=\frac{1}{x}\) b. \(y=\frac{1}{x-5}-2\) c. \(y=\frac{0.5}{x}+3\) d. \(y=\frac{-3}{x+3}\)
Short Answer
Expert verified
For each function:
- a: Same as parent, domain \( x \neq 0 \).
- b: Shift right 5, down 2; domain \( x \neq 5 \).
- c: Vertical compression, up 3; domain \( x \neq 0 \).
- d: Left 3, reflect, stretch 3; domain \( x \neq -3 \).
Step by step solution
01
Understanding the Parent Function
The parent function is given by \( y = \frac{1}{x} \). This is a basic rational function defined everywhere except at \( x = 0 \) where it is undefined because division by zero is not possible. The graph is a hyperbola with two branches, one in the first quadrant and one in the third quadrant.
02
Analyzing Function a
The function in part (a) is \( y = \frac{1}{x} \). Since this is identical to the parent function, there are no transformations. The domain is all real numbers except \( x = 0 \).
03
Transformations in Function b
The function \( y = \frac{1}{x-5} - 2 \) represents two transformations:1. Horizontal shift: The \( x \) is replaced by \( x-5 \), indicating a horizontal shift 5 units to the right.2. Vertical shift: The '-2' indicates a vertical shift 2 units down.The domain is all real numbers except \( x = 5 \).
04
Transformations in Function c
The function \( y = \frac{0.5}{x} + 3 \) has two transformations:1. Vertical stretch: The numerator is 0.5, which compresses the graph vertically compared to \( y = \frac{1}{x} \).2. Vertical shift: The '+3' indicates a vertical shift 3 units up.The domain is all real numbers except \( x = 0 \).
05
Transformations in Function d
The function \( y = \frac{-3}{x+3} \) includes:1. Horizontal shift: \( x \) is replaced by \( x+3 \), indicating a shift 3 units to the left.2. Reflection and vertical stretch: The '-3' in the numerator indicates a reflection across the x-axis and vertical stretching by a factor of 3.The domain is all real numbers except \( x = -3 \).
Unlock Step-by-Step Solutions & Ace Your Exams!
-
Full Textbook Solutions
Get detailed explanations and key concepts
-
Unlimited Al creation
Al flashcards, explanations, exams and more...
-
Ads-free access
To over 500 millions flashcards
-
Money-back guarantee
We refund you if you fail your exam.
Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Parent Function
The parent function for many rational functions is the simple equation \( y = \frac{1}{x} \). This function is one of the most fundamental forms in mathematics known as a rational function. It is defined at all points except where the denominator equals zero, making the domain all real numbers except for \( x = 0 \). The graph of this function is characterized by a hyperbola with two curves, one in the first quadrant and one in the third quadrant. These curves are mirror images of each other.
- The key feature of the parent function is its vertical and horizontal asymptotes at \( x = 0 \) and \( y = 0 \).
- The behavior of the function approaches infinity as \( x \) approaches zero.
Transformations
Transformations modify the graph of the parent function \( y = \frac{1}{x} \) in various ways, including shifting, stretching, compressing, and reflecting. These transformations alter the position or appearance of the graph without changing the fundamental nature of the rational function.
- Horizontal Shift: Replacing \( x \) with \( x - h \) (or \( x + h \)) moves the graph horizontally by \( h \) units. For example, \( y = \frac{1}{x-5} \) is shifted 5 units to the right.
- Vertical Shift: Adding or subtracting a value \( k \) to the function moves the graph up or down. For instance, \( y = \frac{1}{x-5} - 2 \) is shifted down by 2 units.
- Reflection: Multiplying by a negative value \( -a \) reflects the graph across an axis. \( y = \frac{-3}{x+3} \) is reflected across the x-axis.
- Vertical Stretch or Compression: Changing the coefficient in the numerator stretches or compresses the graph vertically. A numerator greater than 1 stretches the graph, while less than 1 compresses it. For instance, \( y = \frac{0.5}{x} \) compresses the graph.
Domain
The domain of a rational function is crucial because it tells us the values of \( x \) where the function is defined. For the parent function \( y = \frac{1}{x} \), the domain is all real numbers except \( x = 0 \), because division by zero is undefined.
Each transformation can affect the domain, mainly due to horizontal shifts.
Each transformation can affect the domain, mainly due to horizontal shifts.
- In \( y = \frac{1}{x-5} - 2 \), the horizontal shift of 5 units makes \( x = 5 \) the point where the function is undefined.
- In \( y = \frac{0.5}{x} + 3 \), the domain remains all real numbers except \( x = 0 \).
- For \( y = \frac{-3}{x+3} \), the shift makes \( x = -3 \) the excluded value from the domain.
Graphing
Graphing a rational function requires knowledge of its parent function and how transformations alter it. Begin by sketching the basic shape of \( y = \frac{1}{x} \), a hyperbola, and apply the transformations systematically.
- Identify vertical and horizontal asymptotes dictated by the domain and any vertical and horizontal shifts.
- Consider any reflections and adjust the graph accordingly. A negative coefficient in the numerator, like in \( y = \frac{-3}{x+3} \), indicates a reflection across the x-axis.
- When vertical stretching or compressing is involved, modify the curvature's steepness appropriately.