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Ch. 3 - Polynomial and Rational Functions
Blitzer - College Algebra 8th Edition
Blitzer8th EditionCollege AlgebraISBN: 9780136970514Not the one you use?Change textbook
Chapter 4, Problem 109

Exercises 107–109 will help you prepare for the material covered in the next section. Determine whether f(x)=x4−2x2+1 is even, odd, or neither. Describe the symmetry, if any, for the graph of f.

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Recall the definitions: A function \( f(x) \) is even if \( f(-x) = f(x) \) for all \( x \), and it is odd if \( f(-x) = -f(x) \) for all \( x \). If neither condition holds, the function is neither even nor odd.
Start by finding \( f(-x) \) for the given function \( f(x) = x^{4} - 2x^{2} + 1 \). Substitute \( -x \) into the function:
\[ f(-x) = (-x)^{4} - 2(-x)^{2} + 1 \]
Simplify each term using the properties of exponents:
\[ (-x)^{4} = x^{4} \quad \text{and} \quad (-x)^{2} = x^{2} \]
So, \( f(-x) = x^{4} - 2x^{2} + 1 \). Compare this with \( f(x) \) to determine if the function is even, odd, or neither, and then describe the symmetry of the graph based on your conclusion.

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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 is even if f(-x) = f(x) for all x in its domain, indicating symmetry about the y-axis. It is odd if f(-x) = -f(x), showing symmetry about the origin. Determining whether a function is even, odd, or neither helps describe its graph's symmetry.
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Function Substitution and Simplification

To test if a function is even or odd, substitute -x into the function and simplify. Comparing the result to the original function f(x) or its negative -f(x) reveals the function's symmetry properties. Accurate algebraic manipulation is essential for this step.
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Graph Symmetry

Graph symmetry relates to the visual properties of the function's graph. Even functions are symmetric about the y-axis, meaning the left and right sides mirror each other. Odd functions have rotational symmetry about the origin, where rotating the graph 180 degrees yields the same graph.
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