Use the four-step procedure for solving variation problems given on page 447 to solve Exercises 1–10. y varies directly as x. y = 65 when x = 5. Find y when x = 12.
Table of contents
- 0. Review of Algebra4h 18m
- 1. Equations & Inequalities3h 18m
- 2. Graphs of Equations1h 43m
- 3. Functions2h 17m
- 4. Polynomial Functions1h 44m
- 5. Rational Functions1h 23m
- 6. Exponential & Logarithmic Functions2h 28m
- 7. Systems of Equations & Matrices4h 5m
- 8. Conic Sections2h 23m
- 9. Sequences, Series, & Induction1h 22m
- 10. Combinatorics & Probability1h 45m
5. Rational Functions
Introduction to Rational Functions
Problem 7
Textbook Question
Provide a short answer to each question. Is ƒ(x)=1/x2 an even or an odd function? What symmetry does its graph exhibit?
Verified step by step guidance1
Recall the definitions: A function \( f(x) \) is even if \( f(-x) = f(x) \) for all \( x \) in the domain, and it is odd if \( f(-x) = -f(x) \) for all \( x \) in the domain.
Given \( f(x) = \frac{1}{x^2} \), compute \( f(-x) \) by substituting \( -x \) into the function: \( f(-x) = \frac{1}{(-x)^2} \).
Simplify \( f(-x) \): since \( (-x)^2 = x^2 \), we have \( f(-x) = \frac{1}{x^2} \).
Compare \( f(-x) \) with \( f(x) \): since \( f(-x) = f(x) \), the function \( f(x) = \frac{1}{x^2} \) is an even function.
Because \( f(x) \) is even, its graph exhibits symmetry about the y-axis.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Even and Odd Functions
A function f(x) is even if f(-x) = f(x) for all x in its domain, meaning its graph is symmetric about the y-axis. It is odd if f(-x) = -f(x), indicating symmetry about the origin. Determining whether a function is even, odd, or neither helps understand its symmetry properties.
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Function Symmetry
Symmetry in functions refers to how their graphs mirror across certain lines or points. Even functions exhibit y-axis symmetry, so the left and right sides of the graph are mirror images. Odd functions have origin symmetry, meaning rotating the graph 180 degrees about the origin leaves it unchanged.
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Evaluating f(-x) for Rational Functions
To test symmetry for functions like f(x) = 1/x², substitute -x into the function and simplify. For rational functions, this often involves powers of x; even powers yield positive results, affecting symmetry. This substitution helps determine if the function is even, odd, or neither.
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