Section 1: Algebra

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NBHM

  1. Which of the following statements are true?
    1. Every group of order 11 is cyclic.
    2. Every group of order 111 is cyclic.
    3. Every group of order 1111 is cyclic.

      Discussion

  2. Let S_n   denote the symmetric group of order n, i.e. the group of all permutations of the n symbols (1, 2, …  , n). Given two permutations sigma and tau in S_n , we define the product sigma tau as their composition got by applying sigma first and then applying tau to the set {1,2, … , n}, Write down the following permutation in S_8 as the product of disjoint cycles:
    (1 4 3 8 7)(5 4 8).
  3. Write down all the permutations in S_4 which are conjugate to the permutation (1 2)(3 4).
  4. Let R be a ring such that x^2 = x for every x \in R . Which of the following statements are true?
    1. x^n for every n \in N and every x \in R
    2. x= -x for every x \in R
    3. R is a commutative ring.
  5. For a prime number p let F_p denote the field consisting of 0, 1, 2, … ,  p – 1 with addition and multiplication modulo p. Which of the following quotient rings are fields?
    1. F_5 [x] / (x^2 + x + 1)
    2. F_2 [x] / (x^3 + x + 1)
    3. F_3 [x] / (x^3 + x + 1)
  6. Let V be the subspace of M_2 (R) consisting of all matrices with trace zero and such that all entries of the first row add up to zero. Write down a basis for V.
  7. Let  V subset of M_n (R) be a subspace of all matrices such that the entries in every row add up to zero and the entries in every column also add up to 0. What is the dimension of V?
  8. Let T : M_2 (R) –> M_2 (R) be a linear transformation defined by T(A) = 2A + 3A^T . Write down the matrix of this transformation with respect to the basis { E_i , 1 \le i \ge 4 } where E_1 = \begin {bmatrix} 1 & 0 0 & 0 \end {bmatrix} , E_2 \begin {bmatrix} 0 & 1 0 & 0 \end {bmatrix} E_3 \begin {bmatrix} 0 & 0 1 & 0 \end {bmatrix} , E_4 = \begin {bmatrix} 0 & 0 1 & 0 \end {bmatrix}
  9. Find the values of \alpha\in R such that the matrix \begin {bmatrix} 3 & \alpha \alpha & 5 \end {bmatrix} has 2 as an eigenvalue.
  10. Let A = (a_{ij} ) \in M_3 (R) be such that a_{ij} = - a_{ji} for all 1 \le i , j \le 3 . If 31 is a eigenvalue of A find it’s other eigenvalues.

View the other sections of this test.

Geometry || Analysis

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