Let M be an n x n matrix with each entry equal to either 0 or 1. Let mij denote the entry in row i and column j. A diagonal entry is one of the form mii for some i. Swapping rows i and j of the matrix M denotes the following action: we swap the values mik and mjk for k = 1,2, ... , n. Swapping two columns is defined analogously. We say that M is rearrangeable if...
2. Let F be a field, n > 1 an integer and consider the F-vector space Mat,,n(F) of n × n matrices over F. Given a matrix A = (aij) E Matn,n(F) and i < n let 1 row,(Α-Σ@y and col,(A)-Žaji CO j-1 j-1 be the sum of entries in row i and column i, respectively. Define C, A EMat,,(F): row,(A)col,(A) for all 1 < i,j < n] C, { A E Matn.n(F) : row,(A) = 0 = col,(A) for...
Let A be an n x n matrix. Then we know the following facts: 1) IfR" has a basis of eigenvectors corresponding to the matrix A, then we can factor the matrix as A = PDP-1 2) If ) is an eigenvalue with algebraic multiplicity equal to k > 1, then the dimension of the A-eigenspace is less than or equal to k. Then if the n x n matrix A has n distinct eigenvalues it can always be factored...
1. Write R' = {(x, y) |X, Y ER} to represent the set of all 1x2 row vectors of real numbers. This is the standard Euclidean plane you all know and love. If such a row vector is multiplied on the right by a 2x2 matrix, then the output is again in R"; such matrices are called linear transformations. 1. Find a linear transformation that rotates the plane R by a radians. That is, find a matrix T such that...
Question 4 [35 marks in totalj An n x n matrix A is called a stochastic matrix if it! satisfies two conditions: (i) all entries of A are non-negative; and (ii) the sum of entries in each column is one. If the (,) entry of A is denoted by any for ij € {1, 2,...,n}, then A is a stochastic matrix when alij 20 for all i and j and I j = 1 for all j. These matrices are...
a) Let I be the n x n identity matrix and let O be the n × n zero matrix . Suppose A is an n × n matrix such that A3 = 0. Show that I + A is invertible and that (I + A)-1 = I – A+ A2. b) Let B and C be n x n matrices. Assume that the product BC is invertible. Show that B and C are both invertible.
4. Let A be an n x n matrix. Define the trace of A by the formula tr(A) = 2 . In other words, the trace of a matrix is the sum of the diagonal entries of the matrix. It is known that for two n x n matrices A and B, the trace has the property that tr(AB) = tr(BA). Each of the following holds more generally, for n x n matrices A and B, but in the interest...
Let A be an n × n real symmetric matrix with its row and column sums both equal to 0. Let λ1, . . . , λn be the eigenvalues of A, with λn = 0, and with corresponding eigenvectors v1,...,vn (these exist because A is real symmetric). Note that vn = (1, . . . , 1). Let A[i] be the result of deleting the ith row and column. Prove that detA[i] = (λ1···λn-1)/n. Thus, the number of spanning...
Problem 5 (a) Let A be an n × m matrix, and suppose that there exists a m × n matrix B such that BA = 1- (i) Let b є Rn be such that the system of equations Ax b has at least one solution. Prove that this solution must be unique. (ii) Must it be the case that the system of equations Ax = b has a solution for every b? Prove or provide a counterexample. (b) Let...