In Exercises 9–16, a) List all possible rational zeros. b) Use synthetic division to test the possible rational zeros and find an actual zero. c) Use the quotient from part (b) to find the remaining zeros of the polynomial function. f(x)=2x3+x2−3x+1
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 25
Textbook Question
Find a polynomial function ƒ(x) of least degree with real coefficients having zeros as given. √3, -√3, 2, 3
Verified step by step guidance1
Identify the zeros of the polynomial function: \( \sqrt{3}, -\sqrt{3}, 2, 3 \). Since the polynomial has real coefficients, these zeros can be used directly to form factors.
Write the factors corresponding to each zero. For a zero \( r \), the factor is \( (x - r) \). So the factors are \( (x - \sqrt{3}), (x + \sqrt{3}), (x - 2), (x - 3) \).
Group the conjugate pair \( (x - \sqrt{3}) \) and \( (x + \sqrt{3}) \) to form a quadratic factor by multiplying them: \( (x - \sqrt{3})(x + \sqrt{3}) = x^2 - (\sqrt{3})^2 = x^2 - 3 \).
Write the polynomial function as the product of the quadratic factor and the remaining linear factors: \( f(x) = (x^2 - 3)(x - 2)(x - 3) \).
Expand the factors step-by-step if needed: first multiply \( (x - 2)(x - 3) \), then multiply the result by \( (x^2 - 3) \) to get the polynomial in standard form.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Polynomial Zeros and Factors
Each zero of a polynomial corresponds to a factor of the form (x - zero). For example, if √3 is a zero, then (x - √3) is a factor. To find the polynomial, multiply all factors corresponding to the given zeros.
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Real Coefficients and Conjugate Pairs
When a polynomial has real coefficients, irrational zeros like √3 must appear in conjugate pairs (√3 and -√3) to ensure the product results in real coefficients. This guarantees the polynomial remains with real numbers only.
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Least Degree Polynomial
The polynomial of least degree that has the given zeros is formed by using each zero exactly once as a factor. This ensures the polynomial is the simplest (lowest degree) that satisfies the zero conditions.
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Standard Form of Polynomials
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