Math Problem Statement
3 roots of a 5th degree polynomial function f(x) are -2,2 and 4+i. which statement describes the number and nature of all roots for the function f of x has 2 real roots and one imaginary root. f of x has 3 real numbers and one imaginary root. f of x has 5 real numbers and one imaginary root. f of x has 3 real roots and 2 imaginary roots
Solution
Given that one of the roots is , we must remember that the coefficients of polynomials with real numbers are real. This means that if a polynomial has a non-real (complex) root, its complex conjugate must also be a root. Therefore, the conjugate of is , and it must also be a root.
Now, the polynomial is of degree 5, and we already know three of its roots: , , and . The conjugate will add another root, giving us 4 roots so far.
Since the degree of the polynomial is 5, there must be one more root. This root must be a real number because complex roots occur in conjugate pairs, and we only need one more root.
Summary of the roots:
- 2 real roots: ,
- 2 complex roots: and
- 1 remaining real root.
Therefore, the statement that best describes the number and nature of all roots is:
f of x has 3 real roots and 2 imaginary roots.
Would you like more details on this explanation or have any further questions?
Here are 5 related questions you might consider:
- What are the general properties of the roots of polynomials with real coefficients?
- How can you factor a polynomial if you know its complex roots?
- What is the significance of the degree of a polynomial function in relation to its roots?
- Can a polynomial of degree 5 have all real roots?
- How are the imaginary roots represented graphically on the complex plane?
Tip: Always remember that the roots of polynomials with real coefficients come in complex conjugate pairs if they are non-real.
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Math Problem Analysis
Mathematical Concepts
Polynomials
Complex Numbers
Conjugates
Formulas
Conjugate of complex number: (a + bi) -> (a - bi)
Fundamental Theorem of Algebra
Theorems
Fundamental Theorem of Algebra
Conjugate Root Theorem
Suitable Grade Level
Grades 10-12