Math Problem Statement

A matrix with m rows and n columns can be represented as A= [aijmxn, 1≤ i ≤m,1≤ j ≤n, i,j∈ N, where are its elements, i is row index and j is column index. Let B = [bij]mxm be a matrix such that bij biji. Which one of matrices has similar properties as the matrix B?

Solution

Given the problem statement:

  1. Matrix A is an m×nm \times n matrix where A=[aij]A = [a_{ij}] with 1im1 \leq i \leq m and 1jn1 \leq j \leq n.
  2. Matrix B is an m×mm \times m matrix where each element bijb_{ij} satisfies bij=bjib_{ij} = b_{ji}.

Since BB is symmetric (bij=bjib_{ij} = b_{ji}), we are asked to identify which other matrices have similar properties to matrix BB.

Properties of Symmetric Matrices:

  1. Symmetry: For any matrix B=[bij]B = [b_{ij}], if BB is symmetric, then bij=bjib_{ij} = b_{ji} for all ii and jj. This means that the matrix is equal to its transpose, i.e., B=BTB = B^T.
  2. Square Matrix: Symmetric matrices are necessarily square matrices (same number of rows and columns).

Similar Matrices:

  • A matrix that shares the property of symmetry (like matrix BB) must also be a square matrix and must satisfy bij=bjib_{ij} = b_{ji}.

Thus, a matrix that has similar properties as BB could be:

  • Any other symmetric m×mm \times m matrix.

Possible Answer:

Matrices that have similar properties as matrix BB are symmetric matrices of the same dimension, i.e., any symmetric m×mm \times m matrix.

Further Considerations:

If BB is a general m×mm \times m symmetric matrix, any matrix that is symmetric and of the same dimension would have similar properties. This could include:

  • Identity matrix ImI_m
  • Zero matrix OmO_m
  • Any other matrix C=[cij]m×mC = [c_{ij}]_{m \times m} where cij=cjic_{ij} = c_{ji}.

Would you like more details or have any questions?


Here are 5 related questions that might interest you:

  1. What are the eigenvalues of a symmetric matrix?
  2. How do you prove that a symmetric matrix is always diagonalizable?
  3. Can a non-square matrix be symmetric?
  4. What is the difference between a diagonal matrix and a symmetric matrix?
  5. How do symmetric matrices relate to quadratic forms?

Tip: Symmetric matrices are crucial in various fields such as physics and engineering, particularly because of their well-behaved eigenvalues and eigenvectors.

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Math Problem Analysis

Mathematical Concepts

Linear Algebra
Matrix Theory

Formulas

Symmetric matrix property: bij = bji

Theorems

Symmetric Matrix Theorem

Suitable Grade Level

Undergraduate (Linear Algebra Course)