Results 1 to 3 of 3

Math Help - [SOLVED] Conditions

  1. #1
    Member
    Joined
    Sep 2009
    Posts
    158

    [SOLVED] Conditions

    If A, B, C are nonzero matrices, show by a counterexample that AB = AC does not imply that B = C.

    I'm not too worried about this.



    Under what extra conditions would you be able to conclude that
    B = C?


    Don't know what I could do here.
    Maybe A,B,C invertible?

    I know that finding a counterexample will give me this answer, but I'm going to bed soon and will do it when I wake up. Thanks
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Flow Master
    mr fantastic's Avatar
    Joined
    Dec 2007
    From
    Zeitgeist
    Posts
    16,948
    Thanks
    5
    Quote Originally Posted by Noxide View Post
    If A, B, C are nonzero matrices, show by a counterexample that AB = AC does not imply that B = C.

    I'm not too worried about this.



    Under what extra conditions would you be able to conclude that
    B = C?


    Don't know what I could do here.
    Maybe A,B,C invertible?

    I know that finding a counterexample will give me this answer, but I'm going to bed soon and will do it when I wake up. Thanks
    B = C if and only if A is invertible.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Member
    Joined
    Sep 2009
    Posts
    158
    Yes.
    If A is invertible then we can multiply by the inverse to find that B = C.

    Thanks
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. [SOLVED] Boundary conditions
    Posted in the Differential Equations Forum
    Replies: 1
    Last Post: May 18th 2010, 01:50 AM
  2. Replies: 2
    Last Post: January 20th 2010, 01:52 PM
  3. Under what conditions does A\(A\B)=B?
    Posted in the Discrete Math Forum
    Replies: 1
    Last Post: September 19th 2009, 11:35 AM
  4. Replies: 2
    Last Post: August 25th 2009, 07:05 PM
  5. Replies: 2
    Last Post: February 22nd 2009, 01:47 PM

Search Tags


/mathhelpforum @mathhelpforum