Theorem 14.7. If f(x) € R[x] is an irreducible polynomial, then deg(f(x)) is either 1 or...
Activity 14.4. Factor f(x) = 24 – 1 in C[x] into a product of irreducible polynomials in C[x]. In addition to what Corollary 14.3 tells us about irreducible polynomials in C[x], it also tells us something about the number of roots that a polynomial of degree n in C must have. You may
Preview Activity 14.1. In previous investigations, we defined irreducible polynomials and showed that irreducible polynomials in polynomial rings over fields play the same role as primes play in Z. In this investigation we will explore some methods to determine when a polynomial is irreducible, with a special emphasis on polynomials with coefficients in C, R, and Q. To begin, we will review the definition and a simple case. Let F be a field. (a) Give a formal definition of what...
Let F=Z_3, the finite field with 3 elements. Let f(x) be an irreducible polynomial in F[x]. Let K=F[x]/(f(x)). We know that if r=[x] in K, then ris a root of f(x). Prove that f(r^3) is also a root of f(x). Which of the following are relevant ingredients for the proof? If a and b are in Z_3 then (ab)^3=(a^3)(b^3) The Remainder Theorem If a and b are in Z_3 then (a+b)^3=2^3+b^3 For all a in Z_3, a^3=a The first isomorphism...
2. (10) Let p be an odd prime. Let f(x) E Q(x) be an irreducible polynomial of degree p whose Galois group is the dihedral group D2p of a regular p-gon. Prove that f(x) has either all real roots precisely one real root or 2. (10) Let p be an odd prime. Let f(x) E Q(x) be an irreducible polynomial of degree p whose Galois group is the dihedral group D2p of a regular p-gon. Prove that f(x) has either...
Let F=Z_3 , the finite field with 3 elements. Let f(x) be an irreducible polynomial in F[x]. Let K=F[x]/(f(x)). We know that if r=[x] in K, then ris a root of f(x). Prove that f(r^3) is also a root of f(x). Which of the following are relevant ingredients for the proof? If a and b are in Z_3 then (a+b)^3=a^3+b^3 If g is an automorphism of K leaves g(r) is a root of f(x) The Remainder Theorem The Factor Theorem...
Let p be an odd prime. Let f(x) ∈ Q(x) be an irreducible polynomial of degree p whose Galois group is the dihedral group D_2p of a regular p-gon. Prove that f (x) has either all real roots or precisely one real root.
Write the polynomial f(x) as a product of irreducible polynomials in the given ring. Explain in each case how you know the factors are irreducible. 1) f(x) -x* + 2x2 +2x 2 in Z3[x]. 2) f(x)4 + 2x3 + 2x2 +x + 1 in Z3[x]. 3) f(x) 2x3-x2 + 3x + 2 in Q[x] 4) f(x) = 5x4-21x2 + 6x-12 in Q[x)
6. One root of the polynomial f(x) = 2x5 – 23x4 + 76x3 – 9x2 – 246c +234 over C is 5 - i. (a) Write f(x) as a product of irreducible polynomials in Q[x]. Show your work. (b) Write f(x) as a product of irreducible polynomials in R[x]. Show your work. (c) Write f(x) as a product of irreducible polynomials in C[x]. Show your work.
14.7. Taylor's theorem and Max/Min values. A statement of Taylor's theorem for functions of two variables and an example are in Part I (section 7) of my online notes if you didn't get it in class. H. Compute the Hessian of the function f(x,y) = y?e evaluated at the point (0,2), ans (lo 8 I. Use the formula involving the gradient and Hessian for z = Q(x, y) to determine the second order Tavlor polynomial for the functions. You should...
Problem 5. Give an example of an irreducible polynomial f ∈ K[x] which has roots a, b, c in its splitting field such that the fields K(a, b) and K(a, c) are not isomorphic over K.