General Results for Polynomial Equations Lesson 2-7 General Results for Polynomial Equations
Objective:
To apply general theorems about polynomial equations. Objective: To apply general theorems about polynomial equations.
The Fundamental Theorem of Algebra:
The Fundamental Theorem of Algebra: In the complex number system consisting of all real and imaginary numbers, if P(x) is a polynomial of degree n (n>0) with complex coefficients, then the equation P(x) = 0 has exactly n roots (providing a double root is counted as 2 roots, a triple root as 3 roots, etc).
The Complex Conjugates Theorem:
The Complex Conjugates Theorem: If P(x) is a polynomial with real coefficients, and a+bi is an imaginary root, then automatically a-bi must also be a root.
Irrational Roots Theorem:
Irrational Roots Theorem: Suppose P(x) is a polynomial with rational coefficients and a and b are rational numbers, such that √b is irrational. If a + √b is a root of the equation P(x) = 0 then a - √b is also a root.
Odd Degree Polynomial Theorem:
Odd Degree Polynomial Theorem: If P(x) is a polynomial of odd degree (1,3,5,7,…) with real coefficients, then the equation P(x) = 0 has at least one real root!
Theorem 5:
Theorem 5: For the equation axn + bxn-1 + … + k = 0, with k ≠ 0 the sum of roots is:
Theorem 5: For the equation axn + bxn-1 + … + k = 0, with k ≠ 0 the sum of roots is:
Theorem 5: For the equation axn + bxn-1 + … + k = 0, with k ≠ 0 the product of roots is:
Theorem 5: For the equation axn + bxn-1 + … + k = 0, with k ≠ 0 the product of roots is:
Theorem 5: For the equation axn + bxn-1 + … + k = 0, with k ≠ 0 the product of roots is:
Given:
Given: What can you identify about this equation?
Given: What can you identify about this equation? 1st: Because this is an odd polynomial it has at least one real root.
Given: What can you identify about this equation? 2nd: Sum of the roots:
Given: What can you identify about this equation? 2nd: Sum of the roots:
Given: What can you identify about this equation? 2nd: Sum of the roots: Which means:
Given: What can you identify about this equation? 3rd: Product of the roots:
Given: What can you identify about this equation? 3rd: Product of the roots:
Given: What can you identify about this equation? 3rd: Product of the roots: Which means:
Assignment: Pgs. 89 - 90 1 – 27 odd