Solve: x4+2x3−x2−4x−2=0
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 108
Textbook Question
Find all complex zeros of each polynomial function. Give exact values. List multiple zeros as necessary.* ƒ(x)=x4+4x3+6x2+4x+1
Verified step by step guidance1
Recognize that the polynomial ƒ(x) = x^4 + 4x^3 + 6x^2 + 4x + 1 resembles the expansion of a binomial expression. Recall the binomial theorem and check if it matches the expansion of (x + 1)^n for some n.
Write down the binomial expansion for (x + 1)^4, which is given by the formula: \[(x + 1)^4 = \sum_{k=0}^4 \binom{4}{k} x^{4-k} 1^k = x^4 + 4x^3 + 6x^2 + 4x + 1.\] Confirm that this matches the given polynomial exactly.
Since the polynomial is equal to \((x + 1)^4\), set the equation to zero to find the zeros: \[(x + 1)^4 = 0.\]
Solve the equation by taking the fourth root of both sides, which leads to \(x + 1 = 0\) because the only root of zero raised to any power is zero itself.
Find the zero by isolating \(x\): \[x = -1.\] Since the factor is raised to the fourth power, the zero \(x = -1\) has multiplicity 4, meaning it is a repeated root four times.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Polynomial Zeros and Roots
Polynomial zeros are the values of x for which the polynomial equals zero. Finding these roots involves solving the equation f(x) = 0. Zeros can be real or complex numbers, and their multiplicity indicates how many times a root repeats.
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Factoring Polynomials
Factoring breaks down a polynomial into simpler polynomials whose product equals the original. Recognizing patterns like the binomial expansion or perfect powers helps simplify the polynomial, making it easier to find zeros by setting each factor to zero.
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Introduction to Factoring Polynomials
Complex Numbers and Roots
Complex numbers include real and imaginary parts and are essential when polynomial roots are not real. Understanding how to express and manipulate complex roots, including using the Fundamental Theorem of Algebra, allows finding all zeros of a polynomial.
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Introduction to Complex Numbers
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