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 4+i4 + i, 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 4+i4 + i is 4i4 - i, and it must also be a root.

Now, the polynomial is of degree 5, and we already know three of its roots: 2-2, 22, and 4+i4 + i. The conjugate 4i4 - i 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: 2-2, 22
  • 2 complex roots: 4+i4 + i and 4i4 - i
  • 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:

  1. What are the general properties of the roots of polynomials with real coefficients?
  2. How can you factor a polynomial if you know its complex roots?
  3. What is the significance of the degree of a polynomial function in relation to its roots?
  4. Can a polynomial of degree 5 have all real roots?
  5. 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