Chapter 2: Problem 11
A polynomial function is described. Find all remaining zeros. Degree: \(4 \quad\) Zeros: \(2 i, 3-i\)
Short Answer
Expert verified
All zeros are: \(2i, -2i, 3-i, 3+i\).
Step by step solution
01
Understand the Conjugate Pairs Theorem
Complex zeros in polynomials with real coefficients occur in conjugate pairs. Since the given zeros include \(2i\) and \(3 - i\), we can conclude that their conjugates, \(-2i\) and \(3 + i\), must also be zeros of the polynomial.
02
Count the Zeros
We know the polynomial is of degree 4, meaning it can have exactly 4 zeros (considering multiplicity). Since we already have four zeros: \(2i, -2i, 3-i,\) and \(3+i\), we have accounted for all the zeros.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Conjugate Pairs
In the context of polynomial functions with real coefficients, conjugate pairs play a crucial role. When a polynomial has a complex zero, such as the given zero
- \(2i\),
- \(3 - i\),
- \(a + bi\)
- \(a - bi\)
- "a" and "b" are real numbers, and "\(i\)" is the imaginary unit with the property \(i^2 = -1\).
- \(2i\) is a zero,
- \(-2i\) must also be a zero.
- Similarly,
- if \(3 - i\) is a zero,
- then \(3 + i\) is also a zero.
Degree of Polynomial
The degree of a polynomial is a vital concept in understanding its nature. It indicates the highest power of the variable present in the polynomial. For example, if a polynomial is of degree 4, the term with the highest power of the variable will be raised to the fourth power.
- In this exercise, the polynomial's degree is given as 4.
- Such a property is significant because it limits the total number of roots (or zeros) a polynomial can have.
- If it has complex roots, their number will match the degree as they pair off with their conjugates wisely.
Complex Numbers
Complex numbers are a core concept when analyzing polynomials, especially when dealing with zeros that are not real numbers. A complex number has a real part and an imaginary part, expressed generally as \(a + bi\), where
- "a" is the real component,
- "b" is the coefficient for the imaginary component,
- and \(i\) is the imaginary unit such that \(i^2 = -1\).
- \(2i\)
- \(3 - i\)
Multiplicity of Roots
Multiplicity refers to the number of times a particular root is a zero for a given polynomial. For example, if a zero appears more than once, it has multiplicity greater than one. This concept is essential when dealing with the degree of a polynomial, as the sum of all multiplicities equals the polynomial's degree.
- In the given exercise, since the polynomial's degree is 4, the total multiplicities combined should equal 4.
- \(2i\),
- \(-2i\),
- \(3 - i\),
- and \(3 + i\)