Determine the different possibilities for the numbers of positive, negative, and nonreal complex zeros of each function.
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- 0. Review of Algebra4h 18m
- 1. Equations & Inequalities3h 18m
- 2. Graphs of Equations1h 43m
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- 4. Polynomial Functions1h 44m
- 5. Rational Functions1h 23m
- 6. Exponential & Logarithmic Functions2h 28m
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- 9. Sequences, Series, & Induction1h 22m
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4. Polynomial Functions
Zeros of Polynomial Functions
Problem 106
Textbook Question
Find all complex zeros of each polynomial function. Give exact values. List multiple zeros as necessary.* ƒ(x)=4x3+3x2+8x+6
Verified step by step guidance1
Start by writing down the polynomial function: \(f(x) = 4x^3 + 3x^2 + 8x + 6\).
Use the Rational Root Theorem to list possible rational zeros. These are of the form \(\pm \frac{p}{q}\), where \(p\) divides the constant term (6) and \(q\) divides the leading coefficient (4). So possible rational roots are \(\pm 1, \pm 2, \pm 3, \pm 6, \pm \frac{1}{2}, \pm \frac{3}{2}, \pm \frac{1}{4}, \pm \frac{3}{4}\).
Test these possible roots by substituting them into \(f(x)\) to find any actual zeros. When you find a root \(r\), use polynomial division or synthetic division to divide \(f(x)\) by \((x - r)\) to reduce the cubic to a quadratic.
Once you have the quadratic factor from the division, solve it using the quadratic formula: \(x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\), where \(a\), \(b\), and \(c\) are coefficients from the quadratic.
Combine the rational root(s) found and the solutions from the quadratic formula to list all complex zeros of the polynomial, including any repeated roots if applicable.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Complex Zeros of Polynomial Functions
Complex zeros are the values of x, possibly including imaginary numbers, that make the polynomial equal to zero. Finding all complex zeros involves solving the polynomial equation f(x) = 0, which may require factoring, synthetic division, or applying the quadratic formula when necessary.
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Polynomial Division and Factoring
Polynomial division, including synthetic division, helps simplify higher-degree polynomials by dividing out known factors. Factoring breaks the polynomial into products of lower-degree polynomials, making it easier to find zeros by setting each factor equal to zero.
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Introduction to Factoring Polynomials
Quadratic Formula
The quadratic formula, x = (-b ± √(b² - 4ac)) / 2a, is used to find exact roots of quadratic equations. When a polynomial is reduced to a quadratic factor, this formula helps find real or complex zeros depending on the discriminant's value.
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