1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Matrix problems

  1. Oct 11, 2008 #1
    1. The problem statement, all variables and given/known data
    1)Find all matrices X that satisfy the equation A*X*B^T = C, in terms of the LU
    factorizations of A and B. State the precise conditions under which there are no

    B^T is the transpose of B.

    2) Let U_1 and U_2 be two upper-triangular matrices. Let Z be an m × n matrix. Let
    X be an unknown matrix that satisfies the equation
    U_1X + XU_2 = Z.
    A. Give an algorithm to find X in O(mn(m+ n)) flops (floating-point operations).
    B. Find conditions on U_1 and U_2 which guarantee the existence of a unique solution
    C. Give a non-trivial example (U_1 is not equal to 0, U_2 is not equal to 0, X is not equal to 0) where those conditions are
    not satisfied and
    U_1X + XU_2 = 0.

    2. Relevant equations

    3. The attempt at a solution
    any hints?
  2. jcsd
  3. Oct 11, 2008 #2
    anyone has any hints? how should i attempt these problems?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook