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
4. Polynomial Functions
Zeros of Polynomial Functions
Problem 35
Textbook Question
Use the Rational Zero Theorem to list all possible rational zeros for each given function.
Verified step by step guidance1
Identify the polynomial function: \(f(x) = x^4 - 6x^3 + 14x^2 - 14x + 5\).
Recall the Rational Zero Theorem: any rational zero, expressed as \(\frac{p}{q}\), must have \(p\) as a factor of the constant term and \(q\) as a factor of the leading coefficient.
Find the factors of the constant term (the last term), which is 5. The factors of 5 are \(\pm 1\) and \(\pm 5\).
Find the factors of the leading coefficient (the coefficient of \(x^4\)), which is 1. The factors of 1 are \(\pm 1\).
List all possible rational zeros by forming all fractions \(\frac{p}{q}\) using the factors found: \(\pm 1\) and \(\pm 5\) (since dividing by 1 does not change the value). So, the possible rational zeros are \(\pm 1\) and \(\pm 5\).
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Rational Zero Theorem
The Rational Zero Theorem provides a list of all possible rational zeros of a polynomial function by considering factors of the constant term and the leading coefficient. Specifically, any rational zero is of the form ±(factor of constant term) / (factor of leading coefficient). This theorem helps narrow down candidates for zeros before testing them.
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Polynomial Functions and Their Zeros
A polynomial function is an expression involving variables raised to whole-number exponents with coefficients. Zeros of a polynomial are values of x that make the function equal to zero. Finding zeros is essential for graphing and solving polynomial equations, and rational zeros are a subset that can be expressed as fractions.
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Factoring and Testing Possible Zeros
After listing possible rational zeros using the Rational Zero Theorem, each candidate must be tested by substitution or synthetic division to determine if it is an actual zero. Factoring the polynomial using confirmed zeros simplifies the function and helps find all roots, including irrational or complex ones.
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Related Practice
Textbook Question
In Exercises 25–32, find an nth-degree polynomial function with real coefficients satisfying the given conditions. If you are using a graphing utility, use it to graph the function and verify the real zeros and the given function value. n=3; -5 and 4+3i are zeros; f(2) = 91
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